drm: Add DRM_FBDEV_EMULATION Kconfig option

Legacy fbdev emulation support via DRM is achieved through KMS FB helpers. Most modesetting drivers enable provide fbdev emulation by default by selecting KMS FB helpers. A few provide a separate Kconfig option for the user to enable or disbale fbdev emulation.

Enabling fbdev emulation is finally a distro-level decision. Having a top level Kconfig option for fbdev emulation helps by providing a uniform way to enable/disable fbdev emulation for any modesetting driver. It also lets us remove unnecessary driver specific Kconfig options that causes bloat.

With a top level Kconfig in place, we can stub out the fb helper functions when not needed without breaking functionality. Having stub functions also prevents drivers to require wrapping fb helper function calls with #ifdefs.

DRM_FBDEV_EMULATION defaults to y since many drivers enable fbdev emulation by default and majority of distributions expect the fbdev interface in the kernel.

For now, this config selects both FB_SYS_* and FB_CFB_* configs as some modesetting drivers use the former and other the later. This needs to be taken care of in a better way.

Signed-off-by Archit Taneja <[email protected]>

---
 drivers/gpu/drm/Kconfig     |  18 +++++++
 drivers/gpu/drm/Makefile    |   4 ++
 include/drm/drm_fb_helper.h | 120 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 142 insertions(+)

drivers/gpu/drm/Kconfig +18 -0

index 151a050..38f83a0 100644
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
 	help
 	  FBDEV helpers for KMS drivers.
 
+config DRM_FBDEV_EMULATION
+	bool "Enable legacy fbdev support for your modesetting driver"
+	depends on DRM
+	select DRM_KMS_HELPER
+	select DRM_KMS_FB_HELPER
+	select FB_SYS_FILLRECT
+	select FB_SYS_COPYAREA
+	select FB_SYS_IMAGEBLIT
+	select FB_SYS_FOPS
+	select FB_CFB_FILLRECT
+	select FB_CFB_COPYAREA
+	select FB_CFB_IMAGEBLIT
+	default y
+	help
+	  Choose this option if you have a need for the legacy fbdev
+	  support. Note that this support also provide the linux console
+	  support on top of your modesetting driver.
+
 config DRM_LOAD_EDID_FIRMWARE
 	bool "Allow to specify an EDID data set instead of probing for it"
 	depends on DRM_KMS_HELPER

drivers/gpu/drm/Makefile +0 -0

index 2c239b9..c1d44b2 100644

drivers/gpu/drm/Makefile +1 -0

+
 drm_kms_helper-$(CONFIG_DRM_KMS_CMA_HELPER) += drm_fb_cma_helper.o
 
 obj-$(CONFIG_DRM_KMS_HELPER) += drm_kms_helper.o

include/drm/drm_fb_helper.h +120 -0

index 21b944c..dbfce1a 100644
@@ -103,6 +103,7 @@ struct drm_fb_helper {
 	bool delayed_hotplug;
 };
 
+#ifdef CONFIG_DRM_FBDEV_EMULATION
 void drm_fb_helper_prepare(struct drm_device *dev, struct drm_fb_helper *helper,
 			   const struct drm_fb_helper_funcs *funcs);
 int drm_fb_helper_init(struct drm_device *dev,

@@ -139,4 +140,123 @@ drm_pick_cmdline_mode(struct drm_fb_helper_connector *fb_helper_conn,
 int drm_fb_helper_add_one_connector(struct drm_fb_helper *fb_helper, struct drm_connector *connector);
 int drm_fb_helper_remove_one_connector(struct drm_fb_helper *fb_helper,
 				       struct drm_connector *connector);
+#else
+static inline void drm_fb_helper_prepare(struct drm_device *dev,
+					struct drm_fb_helper *helper,
+					const struct drm_fb_helper_funcs *funcs)
+{
+}
+
+static inline int drm_fb_helper_init(struct drm_device *dev,
+		       struct drm_fb_helper *helper, int crtc_count,
+		       int max_conn)
+{
+	return 0;
+}
+
+static inline void drm_fb_helper_fini(struct drm_fb_helper *helper)
+{
+}
+
+static inline int drm_fb_helper_blank(int blank, struct fb_info *info)
+{
+	return 0;
+}
+
+static inline int drm_fb_helper_pan_display(struct fb_var_screeninfo *var,
+					    struct fb_info *info)
+{
+	return 0;
+}
+
+static inline int drm_fb_helper_set_par(struct fb_info *info)
+{
+	return 0;
+}
+
+static inline int drm_fb_helper_check_var(struct fb_var_screeninfo *var,
+					  struct fb_info *info)
+{
+	return 0;
+}
+
+static inline bool
+drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper)
+{
+	return true;
+}
+
+static inline void drm_fb_helper_fill_var(struct fb_info *info,
+					  struct drm_fb_helper *fb_helper,
+					  uint32_t fb_width, uint32_t fb_height)
+{
+}
+
+static inline void drm_fb_helper_fill_fix(struct fb_info *info, uint32_t pitch,
+					  uint32_t depth)
+{
+}
+
+static inline int drm_fb_helper_setcmap(struct fb_cmap *cmap,
+					struct fb_info *info)
+{
+	return 0;
+}
+
+static inline int drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper)
+{
+	return 0;
+}
+
+static inline int drm_fb_helper_initial_config(struct drm_fb_helper *fb_helper,
+					       int bpp_sel)
+{
+	return 0;
+}
+
+static inline int
+drm_fb_helper_single_add_all_connectors(struct drm_fb_helper *fb_helper)
+{
+	return 0;
+}
+
+static inline int drm_fb_helper_debug_enter(struct fb_info *info)
+{
+	return 0;
+}
+
+static inline int drm_fb_helper_debug_leave(struct fb_info *info)
+{
+	return 0;
+}
+
+static inline struct drm_display_mode *
+drm_has_preferred_mode(struct drm_fb_helper_connector *fb_connector,
+		       int width, int height)
+{
+	return NULL;
+}
+
+static inline struct drm_display_mode *
+drm_pick_cmdline_mode(struct drm_fb_helper_connector *fb_helper_conn,
+		      int width, int height)
+{
+	return NULL;
+}
+
+static inline int
+drm_fb_helper_add_one_connector(struct drm_fb_helper *fb_helper,
+				struct drm_connector *connector)
+{
+	return 0;
+}
+
+static inline int
+drm_fb_helper_remove_one_connector(struct drm_fb_helper *fb_helper,
+				   struct drm_connector *connector)
+{
+	return 0;
+}
+#endif
+
 #endif

Signature · 2 lines

The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

Quoted 62 lines · Archit Taneja

Legacy fbdev emulation support via DRM is achieved through KMS FB helpers. Most modesetting drivers enable provide fbdev emulation by default by selecting KMS FB helpers. A few provide a separate Kconfig option for the user to enable or disbale fbdev emulation.

Enabling fbdev emulation is finally a distro-level decision. Having a top level Kconfig option for fbdev emulation helps by providing a uniform way to enable/disable fbdev emulation for any modesetting driver. It also lets us remove unnecessary driver specific Kconfig options that causes bloat.

With a top level Kconfig in place, we can stub out the fb helper functions when not needed without breaking functionality. Having stub functions also prevents drivers to require wrapping fb helper function calls with #ifdefs.

DRM_FBDEV_EMULATION defaults to y since many drivers enable fbdev emulation by default and majority of distributions expect the fbdev interface in the kernel.

For now, this config selects both FB_SYS_* and FB_CFB_* configs as some modesetting drivers use the former and other the later. This needs to be taken care of in a better way.

Signed-off-by Archit Taneja <[email protected]>

---
  drivers/gpu/drm/Kconfig     |  18 +++++++
  drivers/gpu/drm/Makefile    |   4 ++
  include/drm/drm_fb_helper.h | 120 ++++++++++++++++++++++++++++++++++++++++++++
  3 files changed, 142 insertions(+)

drivers/gpu/drm/Kconfig +18 -0

index 151a050..38f83a0 100644
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
  	help
  	  FBDEV helpers for KMS drivers.
 
+config DRM_FBDEV_EMULATION
+	bool "Enable legacy fbdev support for your modesetting driver"
+	depends on DRM
+	select DRM_KMS_HELPER
+	select DRM_KMS_FB_HELPER
+	select FB_SYS_FILLRECT
+	select FB_SYS_COPYAREA
+	select FB_SYS_IMAGEBLIT
+	select FB_SYS_FOPS
+	select FB_CFB_FILLRECT
+	select FB_CFB_COPYAREA
+	select FB_CFB_IMAGEBLIT
+	default y
+	help
+	  Choose this option if you have a need for the legacy fbdev
+	  support. Note that this support also provide the linux console
+	  support on top of your modesetting driver.
+
  config DRM_LOAD_EDID_FIRMWARE
  	bool "Allow to specify an EDID data set instead of probing for it"
  	depends on DRM_KMS_HELPER

drivers/gpu/drm/Makefile +0 -0

index 2c239b9..c1d44b2 100644

drivers/gpu/drm/Makefile drm-$(CONFIG_OF) += drm_of.o · line 31

Quoted 7 lines

drivers/gpu/drm/Makefile +3 -0

@@ -25,7 +25,11 @@ drm-$(CONFIG_OF) += drm_of.o
  drm_kms_helper-y := drm_crtc_helper.o drm_dp_helper.o drm_probe_helper.o \
  		drm_plane_helper.o drm_dp_mst_topology.o drm_atomic_helper.o
  drm_kms_helper-$(CONFIG_DRM_LOAD_EDID_FIRMWARE) += drm_edid_load.o
+
+ifeq ($(CONFIG_DRM_FBDEV_EMULATION),y)
  drm_kms_helper-$(CONFIG_DRM_KMS_FB_HELPER) += drm_fb_helper.o
+endif

This should work as

drm_kms_helper-$CONFIG_DRM_FBDEV_EMULATION += drm_fb_helper.o

since both <modename>-y and <modename>-m are merged together.

Legacy fbdev emulation support via DRM is achieved through KMS FB helpers. Most modesetting drivers enable provide fbdev emulation by default by selecting KMS FB helpers. A few provide a separate Kconfig option for the user to enable or disbale fbdev emulation.

Enabling fbdev emulation is finally a distro-level decision. Having a top level Kconfig option for fbdev emulation helps by providing a uniform way to enable/disable fbdev emulation for any modesetting driver. It also lets us remove unnecessary driver specific Kconfig options that causes bloat.

With a top level Kconfig in place, we can stub out the fb helper functions when not needed without breaking functionality. Having stub functions also prevents drivers to require wrapping fb helper function calls with #ifdefs.

DRM_FBDEV_EMULATION defaults to y since many drivers enable fbdev emulation by default and majority of distributions expect the fbdev interface in the kernel.

For now, this config selects both FB_SYS_* and FB_CFB_* configs as some modesetting drivers use the former and other the later. This needs to be taken care of in a better way.

Signed-off-by Archit Taneja <[email protected]>

---
 drivers/gpu/drm/Kconfig     |  18 +++++++
 drivers/gpu/drm/Makefile    |   4 ++
 include/drm/drm_fb_helper.h | 120 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 142 insertions(+)

drivers/gpu/drm/Kconfig +7 -0

index 151a050..38f83a0 100644
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
 	help
 	  FBDEV helpers for KMS drivers.
 
+config DRM_FBDEV_EMULATION
+	bool "Enable legacy fbdev support for your modesetting driver"
+	depends on DRM
+	select DRM_KMS_HELPER
+	select DRM_KMS_FB_HELPER
+	select FB_SYS_FILLRECT
+	select FB_SYS_COPYAREA

drivers/gpu/drm/Kconfig +1 -0

+
 config DRM_LOAD_EDID_FIRMWARE
 	bool "Allow to specify an EDID data set instead of probing for it"
 	depends on DRM_KMS_HELPER

drivers/gpu/drm/Makefile +4 -0

index 2c239b9..c1d44b2 100644
@@ -25,7 +25,11 @@ drm-$(CONFIG_OF) += drm_of.o
 drm_kms_helper-y := drm_crtc_helper.o drm_dp_helper.o drm_probe_helper.o \
 		drm_plane_helper.o drm_dp_mst_topology.o drm_atomic_helper.o
 drm_kms_helper-$(CONFIG_DRM_LOAD_EDID_FIRMWARE) += drm_edid_load.o
+
+ifeq ($(CONFIG_DRM_FBDEV_EMULATION),y)
 drm_kms_helper-$(CONFIG_DRM_KMS_FB_HELPER) += drm_fb_helper.o
+endif
+
 drm_kms_helper-$(CONFIG_DRM_KMS_CMA_HELPER) += drm_fb_cma_helper.o
 
 obj-$(CONFIG_DRM_KMS_HELPER) += drm_kms_helper.o

include/drm/drm_fb_helper.h +120 -0

index 21b944c..dbfce1a 100644
@@ -103,6 +103,7 @@ struct drm_fb_helper {
 	bool delayed_hotplug;
 };
 
+#ifdef CONFIG_DRM_FBDEV_EMULATION
 void drm_fb_helper_prepare(struct drm_device *dev, struct drm_fb_helper *helper,
 			   const struct drm_fb_helper_funcs *funcs);
 int drm_fb_helper_init(struct drm_device *dev,

@@ -139,4 +140,123 @@ drm_pick_cmdline_mode(struct drm_fb_helper_connector *fb_helper_conn,
 int drm_fb_helper_add_one_connector(struct drm_fb_helper *fb_helper, struct drm_connector *connector);
 int drm_fb_helper_remove_one_connector(struct drm_fb_helper *fb_helper,
 				       struct drm_connector *connector);
+#else
+static inline void drm_fb_helper_prepare(struct drm_device *dev,
+					struct drm_fb_helper *helper,
+					const struct drm_fb_helper_funcs *funcs)
+{
+}
+
+static inline int drm_fb_helper_init(struct drm_device *dev,
+		       struct drm_fb_helper *helper, int crtc_count,
+		       int max_conn)
+{
+	return 0;
+}
+
+static inline void drm_fb_helper_fini(struct drm_fb_helper *helper)
+{
+}
+
+static inline int drm_fb_helper_blank(int blank, struct fb_info *info)
+{
+	return 0;
+}
+
+static inline int drm_fb_helper_pan_display(struct fb_var_screeninfo *var,
+					    struct fb_info *info)
+{
+	return 0;
+}
+
+static inline int drm_fb_helper_set_par(struct fb_info *info)
+{
+	return 0;
+}
+
+static inline int drm_fb_helper_check_var(struct fb_var_screeninfo *var,
+					  struct fb_info *info)
+{
+	return 0;
+}
+
+static inline bool
+drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper)
+{
+	return true;
+}
+
+static inline void drm_fb_helper_fill_var(struct fb_info *info,
+					  struct drm_fb_helper *fb_helper,
+					  uint32_t fb_width, uint32_t fb_height)
+{
+}
+
+static inline void drm_fb_helper_fill_fix(struct fb_info *info, uint32_t pitch,
+					  uint32_t depth)
+{
+}
+
+static inline int drm_fb_helper_setcmap(struct fb_cmap *cmap,
+					struct fb_info *info)
+{
+	return 0;
+}
+
+static inline int drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper)
+{
+	return 0;
+}
+
+static inline int drm_fb_helper_initial_config(struct drm_fb_helper *fb_helper,
+					       int bpp_sel)
+{
+	return 0;
+}
+
+static inline int
+drm_fb_helper_single_add_all_connectors(struct drm_fb_helper *fb_helper)
+{
+	return 0;
+}
+
+static inline int drm_fb_helper_debug_enter(struct fb_info *info)
+{
+	return 0;
+}
+
+static inline int drm_fb_helper_debug_leave(struct fb_info *info)
+{
+	return 0;
+}
+
+static inline struct drm_display_mode *
+drm_has_preferred_mode(struct drm_fb_helper_connector *fb_connector,
+		       int width, int height)
+{
+	return NULL;
+}
+
+static inline struct drm_display_mode *
+drm_pick_cmdline_mode(struct drm_fb_helper_connector *fb_helper_conn,
+		      int width, int height)
+{
+	return NULL;
+}
+
+static inline int
+drm_fb_helper_add_one_connector(struct drm_fb_helper *fb_helper,
+				struct drm_connector *connector)
+{
+	return 0;
+}
+
+static inline int
+drm_fb_helper_remove_one_connector(struct drm_fb_helper *fb_helper,
+				   struct drm_connector *connector)
+{
+	return 0;
+}
+#endif
+
 #endif

Signature · 2 lines

The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

Quoted 48 lines · Archit Taneja

Legacy fbdev emulation support via DRM is achieved through KMS FB helpers. Most modesetting drivers enable provide fbdev emulation by default by selecting KMS FB helpers. A few provide a separate Kconfig option for the user to enable or disbale fbdev emulation.

Enabling fbdev emulation is finally a distro-level decision. Having a top level Kconfig option for fbdev emulation helps by providing a uniform way to enable/disable fbdev emulation for any modesetting driver. It also lets us remove unnecessary driver specific Kconfig options that causes bloat.

With a top level Kconfig in place, we can stub out the fb helper functions when not needed without breaking functionality. Having stub functions also prevents drivers to require wrapping fb helper function calls with #ifdefs.

DRM_FBDEV_EMULATION defaults to y since many drivers enable fbdev emulation by default and majority of distributions expect the fbdev interface in the kernel.

For now, this config selects both FB_SYS_* and FB_CFB_* configs as some modesetting drivers use the former and other the later. This needs to be taken care of in a better way.

Signed-off-by Archit Taneja <[email protected]>

---
  drivers/gpu/drm/Kconfig     |  18 +++++++
  drivers/gpu/drm/Makefile    |   4 ++
  include/drm/drm_fb_helper.h | 120 ++++++++++++++++++++++++++++++++++++++++++++
  3 files changed, 142 insertions(+)

drivers/gpu/drm/Kconfig +12 -0

index 151a050..38f83a0 100644
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
  	help
  	  FBDEV helpers for KMS drivers.
 
+config DRM_FBDEV_EMULATION
+	bool "Enable legacy fbdev support for your modesetting driver"
+	depends on DRM
+	select DRM_KMS_HELPER
+	select DRM_KMS_FB_HELPER
+	select FB_SYS_FILLRECT
+	select FB_SYS_COPYAREA
+	select FB_SYS_IMAGEBLIT
+	select FB_SYS_FOPS
+	select FB_CFB_FILLRECT
+	select FB_CFB_COPYAREA
+	select FB_CFB_IMAGEBLIT

drivers/gpu/drm/Kconfig config DRM_KMS_FB_HELPER · line 59

Quoted 5 lines

drivers/gpu/drm/Kconfig +5 -0

+	default y
+	help
+	  Choose this option if you have a need for the legacy fbdev
+	  support. Note that this support also provide the linux console
+	  support on top of your modesetting driver.

Maybe clarify that for linux console support you also need CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.

Quoted 49 lines · Daniel Vetter

Quoted 48 lines · Archit Taneja

Legacy fbdev emulation support via DRM is achieved through KMS FB helpers. Most modesetting drivers enable provide fbdev emulation by default by selecting KMS FB helpers. A few provide a separate Kconfig option for the user to enable or disbale fbdev emulation.

Enabling fbdev emulation is finally a distro-level decision. Having a top level Kconfig option for fbdev emulation helps by providing a uniform way to enable/disable fbdev emulation for any modesetting driver. It also lets us remove unnecessary driver specific Kconfig options that causes bloat.

With a top level Kconfig in place, we can stub out the fb helper functions when not needed without breaking functionality. Having stub functions also prevents drivers to require wrapping fb helper function calls with #ifdefs.

DRM_FBDEV_EMULATION defaults to y since many drivers enable fbdev emulation by default and majority of distributions expect the fbdev interface in the kernel.

For now, this config selects both FB_SYS_* and FB_CFB_* configs as some modesetting drivers use the former and other the later. This needs to be taken care of in a better way.

Signed-off-by Archit Taneja <[email protected]>

---
 drivers/gpu/drm/Kconfig     |  18 +++++++
 drivers/gpu/drm/Makefile    |   4 ++
 include/drm/drm_fb_helper.h | 120 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 142 insertions(+)

drivers/gpu/drm/Kconfig +12 -0

index 151a050..38f83a0 100644
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
 	help
 	  FBDEV helpers for KMS drivers.
 
+config DRM_FBDEV_EMULATION
+	bool "Enable legacy fbdev support for your modesetting driver"
+	depends on DRM
+	select DRM_KMS_HELPER
+	select DRM_KMS_FB_HELPER
+	select FB_SYS_FILLRECT
+	select FB_SYS_COPYAREA
+	select FB_SYS_IMAGEBLIT
+	select FB_SYS_FOPS
+	select FB_CFB_FILLRECT
+	select FB_CFB_COPYAREA
+	select FB_CFB_IMAGEBLIT

Quoted 8 lines

drivers/gpu/drm/Kconfig config DRM_KMS_FB_HELPER · line 59

Quoted 5 lines

drivers/gpu/drm/Kconfig +5 -0

+	default y
+	help
+	  Choose this option if you have a need for the legacy fbdev
+	  support. Note that this support also provide the linux console
+	  support on top of your modesetting driver.

Maybe clarify that for linux console support you also need CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.

DRM_KMS_FB_HELPER selects that for us, right?

Quoted 61 lines · Archit Taneja

Quoted 57 lines · Daniel Vetter

Quoted 43 lines · Archit Taneja

Legacy fbdev emulation support via DRM is achieved through KMS FB helpers. Most modesetting drivers enable provide fbdev emulation by default by selecting KMS FB helpers. A few provide a separate Kconfig option for the user to enable or disbale fbdev emulation.

Enabling fbdev emulation is finally a distro-level decision. Having a top level Kconfig option for fbdev emulation helps by providing a uniform way to enable/disable fbdev emulation for any modesetting driver. It also lets us remove unnecessary driver specific Kconfig options that causes bloat.

With a top level Kconfig in place, we can stub out the fb helper functions when not needed without breaking functionality. Having stub functions also prevents drivers to require wrapping fb helper function calls with #ifdefs.

DRM_FBDEV_EMULATION defaults to y since many drivers enable fbdev emulation by default and majority of distributions expect the fbdev interface in the kernel.

For now, this config selects both FB_SYS_* and FB_CFB_* configs as some modesetting drivers use the former and other the later. This needs to be taken care of in a better way.

Signed-off-by Archit Taneja <[email protected]>

---
  drivers/gpu/drm/Kconfig     |  18 +++++++
  drivers/gpu/drm/Makefile    |   4 ++
  include/drm/drm_fb_helper.h | 120 ++++++++++++++++++++++++++++++++++++++++++++
  3 files changed, 142 insertions(+)

drivers/gpu/drm/Kconfig +7 -0

index 151a050..38f83a0 100644
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
  	help
  	  FBDEV helpers for KMS drivers.
 
+config DRM_FBDEV_EMULATION
+	bool "Enable legacy fbdev support for your modesetting driver"
+	depends on DRM
+	select DRM_KMS_HELPER
+	select DRM_KMS_FB_HELPER
+	select FB_SYS_FILLRECT
+	select FB_SYS_COPYAREA

drivers/gpu/drm/Kconfig config DRM_KMS_FB_HELPER · line 59

Quoted 10 lines

drivers/gpu/drm/Kconfig +10 -0

+	select FB_SYS_IMAGEBLIT
+	select FB_SYS_FOPS
+	select FB_CFB_FILLRECT
+	select FB_CFB_COPYAREA
+	select FB_CFB_IMAGEBLIT
+	default y
+	help
+	  Choose this option if you have a need for the legacy fbdev
+	  support. Note that this support also provide the linux console
+	  support on top of your modesetting driver.

Maybe clarify that for linux console support you also need CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.

Quoted 1 line

DRM_KMS_FB_HELPER selects that for us, right?

Hm right I've missed that. Reminds me that you need one more patch at the end to remove all the various select DRM_KMS_FB_HELPER from all drm drivers. Otherwise this knob here won't work by default if you e.g. select radeon. In general we can't mix explicit options with menu entries with a select.

Quoted 32 lines · Daniel Vetter

Quoted 31 lines · Archit Taneja

Quoted 29 lines · Daniel Vetter

Quoted 15 lines · Archit Taneja

drivers/gpu/drm/Kconfig +7 -0

index 151a050..38f83a0 100644
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
 	help
 	  FBDEV helpers for KMS drivers.
 
+config DRM_FBDEV_EMULATION
+	bool "Enable legacy fbdev support for your modesetting driver"
+	depends on DRM
+	select DRM_KMS_HELPER
+	select DRM_KMS_FB_HELPER
+	select FB_SYS_FILLRECT
+	select FB_SYS_COPYAREA

drivers/gpu/drm/Kconfig config DRM_KMS_FB_HELPER · line 59

Quoted 10 lines

drivers/gpu/drm/Kconfig +10 -0

+	select FB_SYS_IMAGEBLIT
+	select FB_SYS_FOPS
+	select FB_CFB_FILLRECT
+	select FB_CFB_COPYAREA
+	select FB_CFB_IMAGEBLIT
+	default y
+	help
+	  Choose this option if you have a need for the legacy fbdev
+	  support. Note that this support also provide the linux console
+	  support on top of your modesetting driver.

Maybe clarify that for linux console support you also need CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.

Quoted 7 lines

Quoted 1 line

DRM_KMS_FB_HELPER selects that for us, right?

Hm right I've missed that. Reminds me that you need one more patch at the end to remove all the various select DRM_KMS_FB_HELPER from all drm drivers. Otherwise this knob here won't work by default if you e.g. select radeon. In general we can't mix explicit options with menu entries with a select.

I was trying that out. Removing DRM_KMS_FB_HELPER and having DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in their respective xyz_fbdev.c files.

Are you saying that we should remove DRM_KMS_FB_HELPER for such drivers and replace them with 'select DRM_FBDEV_EMULATION'?

Another option would be to provide #ifdef DRM_FBDEV_EMULATION wrap-arounds for fb related function calls/declarations in each driver, something that's already done for i915 and msm drivers.

Quoted 41 lines · Archit Taneja

Quoted 39 lines · Daniel Vetter

Quoted 31 lines · Archit Taneja

Quoted 21 lines · Daniel Vetter

Quoted 20 lines · Archit Taneja

drivers/gpu/drm/Kconfig +12 -0

index 151a050..38f83a0 100644
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
  	help
  	  FBDEV helpers for KMS drivers.
 
+config DRM_FBDEV_EMULATION
+	bool "Enable legacy fbdev support for your modesetting driver"
+	depends on DRM
+	select DRM_KMS_HELPER
+	select DRM_KMS_FB_HELPER
+	select FB_SYS_FILLRECT
+	select FB_SYS_COPYAREA
+	select FB_SYS_IMAGEBLIT
+	select FB_SYS_FOPS
+	select FB_CFB_FILLRECT
+	select FB_CFB_COPYAREA
+	select FB_CFB_IMAGEBLIT

Quoted 8 lines

drivers/gpu/drm/Kconfig config DRM_KMS_FB_HELPER · line 59

Quoted 5 lines

drivers/gpu/drm/Kconfig +5 -0

+	default y
+	help
+	  Choose this option if you have a need for the legacy fbdev
+	  support. Note that this support also provide the linux console
+	  support on top of your modesetting driver.

Maybe clarify that for linux console support you also need CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.

Quoted 1 line

DRM_KMS_FB_HELPER selects that for us, right?

Hm right I've missed that. Reminds me that you need one more patch at the end to remove all the various select DRM_KMS_FB_HELPER from all drm drivers. Otherwise this knob here won't work by default if you e.g. select radeon. In general we can't mix explicit options with menu entries with a select.

Quoted 3 lines

I was trying that out. Removing DRM_KMS_FB_HELPER and having DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in their respective xyz_fbdev.c files.

But with the stubbed out functions that should work, right? Why doesn't it?

Quoted 7 lines

Are you saying that we should remove DRM_KMS_FB_HELPER for such drivers and replace them with 'select DRM_FBDEV_EMULATION'?

Another option would be to provide #ifdef DRM_FBDEV_EMULATION wrap-arounds for fb related function calls/declarations in each driver, something that's already done for i915 and msm drivers.

The problem with the patch as-is the massive amounts of selects the FB helper still has. We need to get rid of them so that when you disable fbdev emulation you can indeed disable fbcon and the entire fbdev subsystem. I've thought that remove the hidden symbol DRM_KMS_FB_HELPER and moving all the selects to DRM_FBDEV_EMULATION should work out? If that doesn't work we need to look again how to better stub things out I think.

Quoted 46 lines · Daniel Vetter

Quoted 44 lines · Archit Taneja

Quoted 32 lines · Daniel Vetter

Quoted 31 lines · Archit Taneja

Quoted 29 lines · Daniel Vetter

Quoted 15 lines · Archit Taneja

drivers/gpu/drm/Kconfig +7 -0

index 151a050..38f83a0 100644
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
 	help
 	  FBDEV helpers for KMS drivers.
 
+config DRM_FBDEV_EMULATION
+	bool "Enable legacy fbdev support for your modesetting driver"
+	depends on DRM
+	select DRM_KMS_HELPER
+	select DRM_KMS_FB_HELPER
+	select FB_SYS_FILLRECT
+	select FB_SYS_COPYAREA

drivers/gpu/drm/Kconfig config DRM_KMS_FB_HELPER · line 59

Quoted 10 lines

drivers/gpu/drm/Kconfig +10 -0

+	select FB_SYS_IMAGEBLIT
+	select FB_SYS_FOPS
+	select FB_CFB_FILLRECT
+	select FB_CFB_COPYAREA
+	select FB_CFB_IMAGEBLIT
+	default y
+	help
+	  Choose this option if you have a need for the legacy fbdev
+	  support. Note that this support also provide the linux console
+	  support on top of your modesetting driver.

Maybe clarify that for linux console support you also need CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.

Quoted 7 lines

Quoted 1 line

DRM_KMS_FB_HELPER selects that for us, right?

Hm right I've missed that. Reminds me that you need one more patch at the end to remove all the various select DRM_KMS_FB_HELPER from all drm drivers. Otherwise this knob here won't work by default if you e.g. select radeon. In general we can't mix explicit options with menu entries with a select.

I was trying that out. Removing DRM_KMS_FB_HELPER and having DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in their respective xyz_fbdev.c files.

Quoted 2 lines

But with the stubbed out functions that should work, right? Why doesn't it?

There are still calls to functions from fb core like fb_set_suspend and register_framebuffer which aren't covered by the drm fb helper functions.

Quoted 7 lines

Quoted 6 lines

Are you saying that we should remove DRM_KMS_FB_HELPER for such drivers and replace them with 'select DRM_FBDEV_EMULATION'?

Another option would be to provide #ifdef DRM_FBDEV_EMULATION wrap-arounds for fb related function calls/declarations in each driver, something that's already done for i915 and msm drivers.

Quoted 6 lines

The problem with the patch as-is the massive amounts of selects the FB helper still has. We need to get rid of them so that when you disable fbdev emulation you can indeed disable fbcon and the entire fbdev subsystem. I've thought that remove the hidden symbol DRM_KMS_FB_HELPER and moving all the selects to DRM_FBDEV_EMULATION should work out? If that doesn't work we need to look again how to better stub things out I think.

That's true. Also, as Jani pointed out, maybe it isn't the best idea to make every kms driver select DRM_FBDEV_EMULATION?

Maybe the drivers that are currently built with fbdev emulation by default can add a 'depends on DRM_FBDEV_EMULATION'? Since the config defaults to y, the drivers should run as is. Later, we could take up each driver and build the fb stuff only when DRM_FBDEV_EMULATION is set, like how we do for i915 and msm?

Quoted 49 lines · Archit Taneja

Quoted 46 lines · Daniel Vetter

Quoted 44 lines · Archit Taneja

Quoted 32 lines · Daniel Vetter

Quoted 31 lines · Archit Taneja

Quoted 29 lines · Daniel Vetter

Quoted 15 lines · Archit Taneja

drivers/gpu/drm/Kconfig +7 -0

index 151a050..38f83a0 100644
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
  	help
  	  FBDEV helpers for KMS drivers.
 
+config DRM_FBDEV_EMULATION
+	bool "Enable legacy fbdev support for your modesetting driver"
+	depends on DRM
+	select DRM_KMS_HELPER
+	select DRM_KMS_FB_HELPER
+	select FB_SYS_FILLRECT
+	select FB_SYS_COPYAREA

drivers/gpu/drm/Kconfig config DRM_KMS_FB_HELPER · line 59

Quoted 10 lines

drivers/gpu/drm/Kconfig +10 -0

+	select FB_SYS_IMAGEBLIT
+	select FB_SYS_FOPS
+	select FB_CFB_FILLRECT
+	select FB_CFB_COPYAREA
+	select FB_CFB_IMAGEBLIT
+	default y
+	help
+	  Choose this option if you have a need for the legacy fbdev
+	  support. Note that this support also provide the linux console
+	  support on top of your modesetting driver.

Maybe clarify that for linux console support you also need CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.

Quoted 7 lines

Quoted 1 line

DRM_KMS_FB_HELPER selects that for us, right?

Hm right I've missed that. Reminds me that you need one more patch at the end to remove all the various select DRM_KMS_FB_HELPER from all drm drivers. Otherwise this knob here won't work by default if you e.g. select radeon. In general we can't mix explicit options with menu entries with a select.

I was trying that out. Removing DRM_KMS_FB_HELPER and having DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in their respective xyz_fbdev.c files.

Quoted 5 lines

Quoted 2 lines

But with the stubbed out functions that should work, right? Why doesn't it?

There are still calls to functions from fb core like fb_set_suspend and register_framebuffer which aren't covered by the drm fb helper functions.

Hm, sounds like we need another patch to stub out fb_set_suspend when fbdev isn't enabled. Is there anything else?

Quoted 15 lines

Quoted 8 lines

Quoted 7 lines

Are you saying that we should remove DRM_KMS_FB_HELPER for such drivers and replace them with 'select DRM_FBDEV_EMULATION'?

Another option would be to provide #ifdef DRM_FBDEV_EMULATION wrap-arounds for fb related function calls/declarations in each driver, something that's already done for i915 and msm drivers.

Quoted 6 lines

The problem with the patch as-is the massive amounts of selects the FB helper still has. We need to get rid of them so that when you disable fbdev emulation you can indeed disable fbcon and the entire fbdev subsystem. I've thought that remove the hidden symbol DRM_KMS_FB_HELPER and moving all the selects to DRM_FBDEV_EMULATION should work out? If that doesn't work we need to look again how to better stub things out I think.

Quoted 8 lines

That's true. Also, as Jani pointed out, maybe it isn't the best idea to make every kms driver select DRM_FBDEV_EMULATION?

Maybe the drivers that are currently built with fbdev emulation by default can add a 'depends on DRM_FBDEV_EMULATION'? Since the config defaults to y, the drivers should run as is. Later, we could take up each driver and build the fb stuff only when DRM_FBDEV_EMULATION is set, like how we do for i915 and msm?

Yeah we definitely can't mix select with a user-visible option. I think we just need to fix up the remaining functions and create stubs for them if needed and then drop all the selects. Well in DRM_FBDEV_EMULATION we should still select for fbcon since otherwise tons of bug reports about "where is my fbcon with kms?".

Quoted 50 lines · Daniel Vetter

Quoted 49 lines · Archit Taneja

Quoted 46 lines · Daniel Vetter

Quoted 44 lines · Archit Taneja

Quoted 32 lines · Daniel Vetter

Quoted 31 lines · Archit Taneja

Quoted 29 lines · Daniel Vetter

Quoted 15 lines · Archit Taneja

drivers/gpu/drm/Kconfig +7 -0

index 151a050..38f83a0 100644
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
 	help
 	  FBDEV helpers for KMS drivers.
 
+config DRM_FBDEV_EMULATION
+	bool "Enable legacy fbdev support for your modesetting driver"
+	depends on DRM
+	select DRM_KMS_HELPER
+	select DRM_KMS_FB_HELPER
+	select FB_SYS_FILLRECT
+	select FB_SYS_COPYAREA

drivers/gpu/drm/Kconfig config DRM_KMS_FB_HELPER · line 59

Quoted 10 lines

drivers/gpu/drm/Kconfig +10 -0

+	select FB_SYS_IMAGEBLIT
+	select FB_SYS_FOPS
+	select FB_CFB_FILLRECT
+	select FB_CFB_COPYAREA
+	select FB_CFB_IMAGEBLIT
+	default y
+	help
+	  Choose this option if you have a need for the legacy fbdev
+	  support. Note that this support also provide the linux console
+	  support on top of your modesetting driver.

Maybe clarify that for linux console support you also need CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.

Quoted 7 lines

Quoted 1 line

DRM_KMS_FB_HELPER selects that for us, right?

Hm right I've missed that. Reminds me that you need one more patch at the end to remove all the various select DRM_KMS_FB_HELPER from all drm drivers. Otherwise this knob here won't work by default if you e.g. select radeon. In general we can't mix explicit options with menu entries with a select.

I was trying that out. Removing DRM_KMS_FB_HELPER and having DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in their respective xyz_fbdev.c files.

Quoted 8 lines

Quoted 5 lines

Quoted 2 lines

But with the stubbed out functions that should work, right? Why doesn't it?

There are still calls to functions from fb core like fb_set_suspend and register_framebuffer which aren't covered by the drm fb helper functions.

Hm, sounds like we need another patch to stub out fb_set_suspend when fbdev isn't enabled. Is there anything else?

There are a handful of fb core functions which are called by drm drivers:

fb_alloc_cmap/fb_dealloc_cmap

fb_sys_read/fb_sys_write

register_framebuffer/unregister_framebuffer/unlink_framebuffer/ remove_conflicting_framebuffers

fb_set_suspend

fb_deferred_io_init/fb_deferred_io_cleanup

framebuffer_alloc/framebuffer_release

#if defined(CONFIG_FB)
#include <linux/fb.h>
#else

Quoted 68 lines · Archit Taneja

Quoted 50 lines · Daniel Vetter

Quoted 49 lines · Archit Taneja

Quoted 46 lines · Daniel Vetter

Quoted 44 lines · Archit Taneja

Quoted 32 lines · Daniel Vetter

Quoted 31 lines · Archit Taneja

Quoted 29 lines · Daniel Vetter

Quoted 15 lines · Archit Taneja

drivers/gpu/drm/Kconfig +7 -0

index 151a050..38f83a0 100644
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
  	help
  	  FBDEV helpers for KMS drivers.
 
+config DRM_FBDEV_EMULATION
+	bool "Enable legacy fbdev support for your modesetting driver"
+	depends on DRM
+	select DRM_KMS_HELPER
+	select DRM_KMS_FB_HELPER
+	select FB_SYS_FILLRECT
+	select FB_SYS_COPYAREA

drivers/gpu/drm/Kconfig config DRM_KMS_FB_HELPER · line 59

Quoted 10 lines

drivers/gpu/drm/Kconfig +10 -0

+	select FB_SYS_IMAGEBLIT
+	select FB_SYS_FOPS
+	select FB_CFB_FILLRECT
+	select FB_CFB_COPYAREA
+	select FB_CFB_IMAGEBLIT
+	default y
+	help
+	  Choose this option if you have a need for the legacy fbdev
+	  support. Note that this support also provide the linux console
+	  support on top of your modesetting driver.

Maybe clarify that for linux console support you also need CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.

Quoted 7 lines

Quoted 1 line

DRM_KMS_FB_HELPER selects that for us, right?

Hm right I've missed that. Reminds me that you need one more patch at the end to remove all the various select DRM_KMS_FB_HELPER from all drm drivers. Otherwise this knob here won't work by default if you e.g. select radeon. In general we can't mix explicit options with menu entries with a select.

I was trying that out. Removing DRM_KMS_FB_HELPER and having DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in their respective xyz_fbdev.c files.

Quoted 8 lines

Quoted 5 lines

Quoted 2 lines

But with the stubbed out functions that should work, right? Why doesn't it?

There are still calls to functions from fb core like fb_set_suspend and register_framebuffer which aren't covered by the drm fb helper functions.

Hm, sounds like we need another patch to stub out fb_set_suspend when fbdev isn't enabled. Is there anything else?

There are a handful of fb core functions which are called by drm drivers:

fb_alloc_cmap/fb_dealloc_cmap

fb_sys_read/fb_sys_write

Quoted 8 lines

register_framebuffer/unregister_framebuffer/unlink_framebuffer/ remove_conflicting_framebuffers

fb_set_suspend

fb_deferred_io_init/fb_deferred_io_cleanup

framebuffer_alloc/framebuffer_release

Hm yeah that's somewhat annoying indeed. What about the following:
1. We move all the #include <linux/fb.h> from drivers into drm_fb_helper.h

2. Then we add stubs for these functions in drm_fb_helper.h, like this

#if defined(CONFIG_FB)
#include <linux/fb.h>
#else

/* static inline stubs for all the fb stuff used by kms drivers */ #endif

Imo this makes sense since kms drivers really have a bit a special situation with fbdev. They're not full-blown fbdev drivers and can be useful fully without fbdev.

What do you think?

Quoted 68 lines · Archit Taneja

Quoted 50 lines · Daniel Vetter

Quoted 49 lines · Archit Taneja

Quoted 46 lines · Daniel Vetter

Quoted 44 lines · Archit Taneja

Quoted 32 lines · Daniel Vetter

Quoted 31 lines · Archit Taneja

Quoted 29 lines · Daniel Vetter

Quoted 15 lines · Archit Taneja

drivers/gpu/drm/Kconfig +7 -0

index 151a050..38f83a0 100644
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
  	help
  	  FBDEV helpers for KMS drivers.
 
+config DRM_FBDEV_EMULATION
+	bool "Enable legacy fbdev support for your modesetting driver"
+	depends on DRM
+	select DRM_KMS_HELPER
+	select DRM_KMS_FB_HELPER
+	select FB_SYS_FILLRECT
+	select FB_SYS_COPYAREA

drivers/gpu/drm/Kconfig config DRM_KMS_FB_HELPER · line 59

Quoted 10 lines

drivers/gpu/drm/Kconfig +10 -0

+	select FB_SYS_IMAGEBLIT
+	select FB_SYS_FOPS
+	select FB_CFB_FILLRECT
+	select FB_CFB_COPYAREA
+	select FB_CFB_IMAGEBLIT
+	default y
+	help
+	  Choose this option if you have a need for the legacy fbdev
+	  support. Note that this support also provide the linux console
+	  support on top of your modesetting driver.

Maybe clarify that for linux console support you also need CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.

Quoted 7 lines

Quoted 1 line

DRM_KMS_FB_HELPER selects that for us, right?

Hm right I've missed that. Reminds me that you need one more patch at the end to remove all the various select DRM_KMS_FB_HELPER from all drm drivers. Otherwise this knob here won't work by default if you e.g. select radeon. In general we can't mix explicit options with menu entries with a select.

I was trying that out. Removing DRM_KMS_FB_HELPER and having DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in their respective xyz_fbdev.c files.

Quoted 8 lines

Quoted 5 lines

Quoted 2 lines

But with the stubbed out functions that should work, right? Why doesn't it?

There are still calls to functions from fb core like fb_set_suspend and register_framebuffer which aren't covered by the drm fb helper functions.

Hm, sounds like we need another patch to stub out fb_set_suspend when fbdev isn't enabled. Is there anything else?

There are a handful of fb core functions which are called by drm drivers:

fb_alloc_cmap/fb_dealloc_cmap

fb_sys_read/fb_sys_write

Quoted 8 lines

register_framebuffer/unregister_framebuffer/unlink_framebuffer/ remove_conflicting_framebuffers

fb_set_suspend

fb_deferred_io_init/fb_deferred_io_cleanup

framebuffer_alloc/framebuffer_release

Hm yeah that's somewhat annoying indeed. What about the following:
1. We move all the #include <linux/fb.h> from drivers into drm_fb_helper.h

2. Then we add stubs for these functions in drm_fb_helper.h, like this

#if defined(CONFIG_FB)
#include <linux/fb.h>
#else

/* static inline stubs for all the fb stuff used by kms drivers */ #endif

Imo this makes sense since kms drivers really have a bit a special situation with fbdev. They're not full-blown fbdev drivers and can be useful fully without fbdev.

Hi,

Quoted 87 lines · Daniel Vetter

Quoted 68 lines · Archit Taneja

Quoted 50 lines · Daniel Vetter

Quoted 49 lines · Archit Taneja

Quoted 46 lines · Daniel Vetter

Quoted 44 lines · Archit Taneja

Quoted 32 lines · Daniel Vetter

Quoted 31 lines · Archit Taneja

Quoted 29 lines · Daniel Vetter

Quoted 15 lines · Archit Taneja

drivers/gpu/drm/Kconfig +7 -0

index 151a050..38f83a0 100644
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
 	help
 	  FBDEV helpers for KMS drivers.
 
+config DRM_FBDEV_EMULATION
+	bool "Enable legacy fbdev support for your modesetting driver"
+	depends on DRM
+	select DRM_KMS_HELPER
+	select DRM_KMS_FB_HELPER
+	select FB_SYS_FILLRECT
+	select FB_SYS_COPYAREA

drivers/gpu/drm/Kconfig config DRM_KMS_FB_HELPER · line 59

Quoted 10 lines

drivers/gpu/drm/Kconfig +10 -0

+	select FB_SYS_IMAGEBLIT
+	select FB_SYS_FOPS
+	select FB_CFB_FILLRECT
+	select FB_CFB_COPYAREA
+	select FB_CFB_IMAGEBLIT
+	default y
+	help
+	  Choose this option if you have a need for the legacy fbdev
+	  support. Note that this support also provide the linux console
+	  support on top of your modesetting driver.

Maybe clarify that for linux console support you also need CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.

Quoted 7 lines

Quoted 1 line

DRM_KMS_FB_HELPER selects that for us, right?

Hm right I've missed that. Reminds me that you need one more patch at the end to remove all the various select DRM_KMS_FB_HELPER from all drm drivers. Otherwise this knob here won't work by default if you e.g. select radeon. In general we can't mix explicit options with menu entries with a select.

I was trying that out. Removing DRM_KMS_FB_HELPER and having DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in their respective xyz_fbdev.c files.

Quoted 8 lines

Quoted 5 lines

Quoted 2 lines

But with the stubbed out functions that should work, right? Why doesn't it?

There are still calls to functions from fb core like fb_set_suspend and register_framebuffer which aren't covered by the drm fb helper functions.

Hm, sounds like we need another patch to stub out fb_set_suspend when fbdev isn't enabled. Is there anything else?

There are a handful of fb core functions which are called by drm drivers:

fb_alloc_cmap/fb_dealloc_cmap

fb_sys_read/fb_sys_write

Quoted 8 lines

register_framebuffer/unregister_framebuffer/unlink_framebuffer/ remove_conflicting_framebuffers

fb_set_suspend

fb_deferred_io_init/fb_deferred_io_cleanup

framebuffer_alloc/framebuffer_release

Hm yeah that's somewhat annoying indeed. What about the following:
1. We move all the #include <linux/fb.h> from drivers into drm_fb_helper.h

2. Then we add stubs for these functions in drm_fb_helper.h, like this

#if defined(CONFIG_FB)
#include <linux/fb.h>
#else

Quoted 7 lines

/* static inline stubs for all the fb stuff used by kms drivers */ #endif

Imo this makes sense since kms drivers really have a bit a special situation with fbdev. They're not full-blown fbdev drivers and can be useful fully without fbdev.

I was trying this out. Removing 'linux/fb.h' and replacing stub fb funcs won't really work because struct declarations(like fb_info) also get removed.

I considered placing '#if IS_ENABLED(CONFIG_FB)' within linux/fb.h itself, but that seemed a bit too intrusive.

This is what I'm currently doing:

- Some funcs, like framebufer_alloc/release, alloc_cmap/dealloc_cmap would actually benefit if we have drm fb helpers for them. They are used in exactly the same manner by all the drivers.

- For the rest of the functions that are sparsely used, I was considering making very simple drm_fb_* wrapper functions. Something like:

void drm_fb_helper_deferred_io_init(struct drm_fb_helper *helper)

{
	if (helper->fbdev)
		fb_deferred_io_init(helper->fbdev);
}

We could have all fb calls called within drm_fb_helper.c, creating drm_fb_helper_* stub functions would then be an easier task. What do you think?

Quoted 115 lines · Archit Taneja

Hi,

Quoted 87 lines · Daniel Vetter

Quoted 68 lines · Archit Taneja

Quoted 50 lines · Daniel Vetter

Quoted 49 lines · Archit Taneja

Quoted 46 lines · Daniel Vetter

Quoted 44 lines · Archit Taneja

Quoted 32 lines · Daniel Vetter

Quoted 31 lines · Archit Taneja

Quoted 29 lines · Daniel Vetter

Quoted 15 lines · Archit Taneja

drivers/gpu/drm/Kconfig +7 -0

index 151a050..38f83a0 100644
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
   help
     FBDEV helpers for KMS drivers.
 
+config DRM_FBDEV_EMULATION
+   bool "Enable legacy fbdev support for your modesetting driver"
+   depends on DRM
+   select DRM_KMS_HELPER
+   select DRM_KMS_FB_HELPER
+   select FB_SYS_FILLRECT
+   select FB_SYS_COPYAREA

drivers/gpu/drm/Kconfig config DRM_KMS_FB_HELPER · line 59

Quoted 10 lines

drivers/gpu/drm/Kconfig +10 -0

+   select FB_SYS_IMAGEBLIT
+   select FB_SYS_FOPS
+   select FB_CFB_FILLRECT
+   select FB_CFB_COPYAREA
+   select FB_CFB_IMAGEBLIT
+   default y
+   help
+     Choose this option if you have a need for the legacy fbdev
+     support. Note that this support also provide the linux console
+     support on top of your modesetting driver.

Maybe clarify that for linux console support you also need CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.

Quoted 7 lines

Quoted 1 line

DRM_KMS_FB_HELPER selects that for us, right?

Hm right I've missed that. Reminds me that you need one more patch at the end to remove all the various select DRM_KMS_FB_HELPER from all drm drivers. Otherwise this knob here won't work by default if you e.g. select radeon. In general we can't mix explicit options with menu entries with a select.

I was trying that out. Removing DRM_KMS_FB_HELPER and having DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in their respective xyz_fbdev.c files.

Quoted 8 lines

Quoted 5 lines

Quoted 2 lines

But with the stubbed out functions that should work, right? Why doesn't it?

There are still calls to functions from fb core like fb_set_suspend and register_framebuffer which aren't covered by the drm fb helper functions.

Hm, sounds like we need another patch to stub out fb_set_suspend when fbdev isn't enabled. Is there anything else?

There are a handful of fb core functions which are called by drm drivers:

fb_alloc_cmap/fb_dealloc_cmap

fb_sys_read/fb_sys_write

Quoted 8 lines

register_framebuffer/unregister_framebuffer/unlink_framebuffer/ remove_conflicting_framebuffers

fb_set_suspend

fb_deferred_io_init/fb_deferred_io_cleanup

framebuffer_alloc/framebuffer_release

Hm yeah that's somewhat annoying indeed. What about the following:
1. We move all the #include <linux/fb.h> from drivers into drm_fb_helper.h

2. Then we add stubs for these functions in drm_fb_helper.h, like this

#if defined(CONFIG_FB)
#include <linux/fb.h>
#else

Quoted 7 lines

/* static inline stubs for all the fb stuff used by kms drivers */ #endif

Imo this makes sense since kms drivers really have a bit a special situation with fbdev. They're not full-blown fbdev drivers and can be useful fully without fbdev.

I was trying this out. Removing 'linux/fb.h' and replacing stub fb funcs won't really work because struct declarations(like fb_info) also get removed.

I considered placing '#if IS_ENABLED(CONFIG_FB)' within linux/fb.h itself, but that seemed a bit too intrusive.

This is what I'm currently doing:

- Some funcs, like framebufer_alloc/release, alloc_cmap/dealloc_cmap would actually benefit if we have drm fb helpers for them. They are used in exactly the same manner by all the drivers.

- For the rest of the functions that are sparsely used, I was considering making very simple drm_fb_* wrapper functions. Something like:

void drm_fb_helper_deferred_io_init(struct drm_fb_helper *helper)

Quoted 8 lines

{
      if (helper->fbdev)
              fb_deferred_io_init(helper->fbdev);
}

We could have all fb calls called within drm_fb_helper.c, creating drm_fb_helper_* stub functions would then be an easier task. What do you think?

That's actually an option I considered, but I hoped we could do it with less work. If this indeed works and you can create the patch that would be awesome.

Thanks, Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

Any updates on this or too much distractions? I really think doing this would be awesome for the drm subsystem, instead of reinventing this wheel for each driver.

-Daniel

Quoted 134 lines · Daniel Vetter

Quoted 115 lines · Archit Taneja

Hi,

Quoted 87 lines · Daniel Vetter

Quoted 68 lines · Archit Taneja

Quoted 50 lines · Daniel Vetter

Quoted 49 lines · Archit Taneja

Quoted 46 lines · Daniel Vetter

Quoted 44 lines · Archit Taneja

Quoted 32 lines · Daniel Vetter

Quoted 31 lines · Archit Taneja

Quoted 29 lines · Daniel Vetter

Quoted 25 lines · Archit Taneja

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 151a050..38f83a0 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
help
FBDEV helpers for KMS drivers.

+config DRM_FBDEV_EMULATION
+ bool "Enable legacy fbdev support for your modesetting driver"
+ depends on DRM
+ select DRM_KMS_HELPER
+ select DRM_KMS_FB_HELPER
+ select FB_SYS_FILLRECT
+ select FB_SYS_COPYAREA
+ select FB_SYS_IMAGEBLIT
+ select FB_SYS_FOPS
+ select FB_CFB_FILLRECT
+ select FB_CFB_COPYAREA
+ select FB_CFB_IMAGEBLIT
+ default y
+ help
+ Choose this option if you have a need for the legacy fbdev
+ support. Note that this support also provide the linux console
+ support on top of your modesetting driver.

Maybe clarify that for linux console support you also need CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.

Quoted 7 lines

Quoted 1 line

DRM_KMS_FB_HELPER selects that for us, right?

Hm right I've missed that. Reminds me that you need one more patch at the end to remove all the various select DRM_KMS_FB_HELPER from all drm drivers. Otherwise this knob here won't work by default if you e.g. select radeon. In general we can't mix explicit options with menu entries with a select.

I was trying that out. Removing DRM_KMS_FB_HELPER and having DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in their respective xyz_fbdev.c files.

Quoted 8 lines

Quoted 5 lines

Quoted 2 lines

But with the stubbed out functions that should work, right? Why doesn't it?

There are still calls to functions from fb core like fb_set_suspend and register_framebuffer which aren't covered by the drm fb helper functions.

Hm, sounds like we need another patch to stub out fb_set_suspend when fbdev isn't enabled. Is there anything else?

There are a handful of fb core functions which are called by drm drivers:

fb_alloc_cmap/fb_dealloc_cmap

fb_sys_read/fb_sys_write

Quoted 8 lines

register_framebuffer/unregister_framebuffer/unlink_framebuffer/ remove_conflicting_framebuffers

fb_set_suspend

fb_deferred_io_init/fb_deferred_io_cleanup

framebuffer_alloc/framebuffer_release

Hm yeah that's somewhat annoying indeed. What about the following:
1. We move all the #include <linux/fb.h> from drivers into drm_fb_helper.h

2. Then we add stubs for these functions in drm_fb_helper.h, like this

#if defined(CONFIG_FB)
#include <linux/fb.h>
#else

Quoted 7 lines

/* static inline stubs for all the fb stuff used by kms drivers */ #endif

Imo this makes sense since kms drivers really have a bit a special situation with fbdev. They're not full-blown fbdev drivers and can be useful fully without fbdev.

I was trying this out. Removing 'linux/fb.h' and replacing stub fb funcs won't really work because struct declarations(like fb_info) also get removed.

I considered placing '#if IS_ENABLED(CONFIG_FB)' within linux/fb.h itself, but that seemed a bit too intrusive.

This is what I'm currently doing:

- Some funcs, like framebufer_alloc/release, alloc_cmap/dealloc_cmap would actually benefit if we have drm fb helpers for them. They are used in exactly the same manner by all the drivers.

- For the rest of the functions that are sparsely used, I was considering making very simple drm_fb_* wrapper functions. Something like:

void drm_fb_helper_deferred_io_init(struct drm_fb_helper *helper)

Quoted 8 lines

{
       if (helper->fbdev)
               fb_deferred_io_init(helper->fbdev);
}

We could have all fb calls called within drm_fb_helper.c, creating drm_fb_helper_* stub functions would then be an easier task. What do you think?

That's actually an option I considered, but I hoped we could do it with less work. If this indeed works and you can create the patch that would be awesome.

Thanks, Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

Hi,

Quoted 4 lines · Daniel Vetter

Any updates on this or too much distractions? I really think doing this would be awesome for the drm subsystem, instead of reinventing this wheel for each driver.

I'd started on this again. I've got more free time now than before, so I should have something in a week or so. I agree it will help a lot (there are already two new drivers since we started discussing this!)

Archit

Quoted 180 lines

-Daniel

Quoted 173 lines · Daniel Vetter

Quoted 151 lines · Archit Taneja

Hi,

Quoted 119 lines · Daniel Vetter

Quoted 97 lines · Archit Taneja

Quoted 76 lines · Daniel Vetter

Quoted 74 lines · Archit Taneja

Quoted 68 lines · Daniel Vetter

Quoted 57 lines · Archit Taneja

Quoted 44 lines · Daniel Vetter

Quoted 39 lines · Archit Taneja

Quoted 35 lines · Daniel Vetter

On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 151a050..38f83a0 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
help
FBDEV helpers for KMS drivers.

+config DRM_FBDEV_EMULATION
+ bool "Enable legacy fbdev support for your modesetting
driver"
+ depends on DRM
+ select DRM_KMS_HELPER
+ select DRM_KMS_FB_HELPER
+ select FB_SYS_FILLRECT
+ select FB_SYS_COPYAREA
+ select FB_SYS_IMAGEBLIT
+ select FB_SYS_FOPS
+ select FB_CFB_FILLRECT
+ select FB_CFB_COPYAREA
+ select FB_CFB_IMAGEBLIT
+ default y
+ help
+ Choose this option if you have a need for the legacy
fbdev
+ support. Note that this support also provide the linux
console
+ support on top of your modesetting driver.

Maybe clarify that for linux console support you also need
CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.

Quoted 1 line

DRM_KMS_FB_HELPER selects that for us, right?

Quoted 9 lines

Hm right I've missed that. Reminds me that you need one more patch at the
end to remove all the various select DRM_KMS_FB_HELPER from all drm
drivers. Otherwise this knob here won't work by default if you e.g. select
radeon. In general we can't mix explicit options with menu entries with a
select.

Quoted 4 lines

I was trying that out. Removing DRM_KMS_FB_HELPER and having DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in
their respective xyz_fbdev.c files.

But with the stubbed out functions that should work, right? Why doesn't
it?

Quoted 8 lines

Quoted 4 lines

There are still calls to functions from fb core like fb_set_suspend and
register_framebuffer which aren't covered by the drm fb helper functions.

Hm, sounds like we need another patch to stub out fb_set_suspend when fbdev isn't enabled. Is there anything else?

There are a handful of fb core functions which are called by drm drivers:

fb_alloc_cmap/fb_dealloc_cmap

fb_sys_read/fb_sys_write

Quoted 8 lines

register_framebuffer/unregister_framebuffer/unlink_framebuffer/ remove_conflicting_framebuffers

fb_set_suspend

fb_deferred_io_init/fb_deferred_io_cleanup

framebuffer_alloc/framebuffer_release

Hm yeah that's somewhat annoying indeed. What about the following:
1. We move all the #include <linux/fb.h> from drivers into drm_fb_helper.h

2. Then we add stubs for these functions in drm_fb_helper.h, like this

#if defined(CONFIG_FB)
#include <linux/fb.h>
#else

Quoted 7 lines

/* static inline stubs for all the fb stuff used by kms drivers */ #endif

Imo this makes sense since kms drivers really have a bit a special situation with fbdev. They're not full-blown fbdev drivers and can be useful fully without fbdev.

I was trying this out. Removing 'linux/fb.h' and replacing stub fb funcs won't really work because struct declarations(like fb_info) also get removed.

I considered placing '#if IS_ENABLED(CONFIG_FB)' within linux/fb.h itself,
but that seemed a bit too intrusive.

This is what I'm currently doing:

- Some funcs, like framebufer_alloc/release, alloc_cmap/dealloc_cmap would
actually benefit if we have drm fb helpers for them. They are used in exactly the same manner by all the drivers.

- For the rest of the functions that are sparsely used, I was considering
making very simple drm_fb_* wrapper functions. Something like:

void drm_fb_helper_deferred_io_init(struct drm_fb_helper *helper)

Quoted 8 lines

{
       if (helper->fbdev)
               fb_deferred_io_init(helper->fbdev);
}

We could have all fb calls called within drm_fb_helper.c, creating drm_fb_helper_* stub functions would then be an easier task. What do you think?

That's actually an option I considered, but I hoped we could do it with less work. If this indeed works and you can create the patch that would be
awesome.

Thanks, Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project

I think that what have been done by Rob with module_param is also a good idea:
https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/drivers/gpu/drm/msm/msm_drv.c?id=e90dfec78ec288d6c89a7b508a5c5d4ae8b7f934

Can you mix compilation flag and module param ?

Quoted 4 lines · Benjamin Gaignard

I think that what have been done by Rob with module_param is also a good idea:
https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/drivers/gpu/drm/msm/msm_drv.c?id=e90dfec78ec288d6c89a7b508a5c5d4ae8b7f934

Can you mix compilation flag and module param ?

Hm, the point of the kconfig is to not require all the legacy baggage from fbdev. But I guess a module option could be added later on too. bochs has it too.

Quoted 10 lines · Daniel Vetter

Quoted 4 lines · Benjamin Gaignard

I think that what have been done by Rob with module_param is also a good idea:
https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/drivers/gpu/drm/msm/msm_drv.c?id=e90dfec78ec288d6c89a7b508a5c5d4ae8b7f934

Can you mix compilation flag and module param ?

Hm, the point of the kconfig is to not require all the legacy baggage from fbdev. But I guess a module option could be added later on too. bochs has it too.

I think the option would primarily be useful for testing. I've often needed to test modesetting code without fbdev getting in the way and the only way to currently do that is by recompiling with legacy fbdev disabled. The option would allow an fbdev-enabled kernel to be used but disable the fbdev code if desired.

Thierry

_______________________________________________
dri-devel mailing list
[email protected]
http://lists.freedesktop.org/mailman/listinfo/dri-devel

Hi,

I think that what have been done by Rob with module_param is also a good idea:
https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/drivers/gpu/drm/msm/msm_drv.c?id=e90dfec78ec288d6c89a7b508a5c5d4ae8b7f934

Can you mix compilation flag and module param ?

Benjamin

2015-06-30 9:56 GMT+02:00 Archit Taneja <[email protected]>:

Quoted 200 lines

Hi,

Quoted 4 lines · Daniel Vetter

Any updates on this or too much distractions? I really think doing this would be awesome for the drm subsystem, instead of reinventing this wheel for each driver.

I'd started on this again. I've got more free time now than before, so I should have something in a week or so. I agree it will help a lot (there are already two new drivers since we started discussing this!)

Archit

Quoted 180 lines

-Daniel

Quoted 173 lines · Daniel Vetter

Quoted 151 lines · Archit Taneja

Hi,

Quoted 119 lines · Daniel Vetter

Quoted 97 lines · Archit Taneja

Quoted 76 lines · Daniel Vetter

Quoted 74 lines · Archit Taneja

Quoted 68 lines · Daniel Vetter

Quoted 57 lines · Archit Taneja

Quoted 44 lines · Daniel Vetter

Quoted 40 lines · Archit Taneja

On 03/10/2015 03:17 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 151a050..38f83a0 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
help
FBDEV helpers for KMS drivers.

+config DRM_FBDEV_EMULATION
+ bool "Enable legacy fbdev support for your modesetting
driver"
+ depends on DRM
+ select DRM_KMS_HELPER
+ select DRM_KMS_FB_HELPER
+ select FB_SYS_FILLRECT
+ select FB_SYS_COPYAREA
+ select FB_SYS_IMAGEBLIT
+ select FB_SYS_FOPS
+ select FB_CFB_FILLRECT
+ select FB_CFB_COPYAREA
+ select FB_CFB_IMAGEBLIT
+ default y
+ help
+ Choose this option if you have a need for the legacy
fbdev
+ support. Note that this support also provide the linux
console
+ support on top of your modesetting driver.

Maybe clarify that for linux console support you also need
CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.

DRM_KMS_FB_HELPER selects that for us, right?

Quoted 9 lines

Hm right I've missed that. Reminds me that you need one more patch at the
end to remove all the various select DRM_KMS_FB_HELPER from all drm
drivers. Otherwise this knob here won't work by default if you e.g. select
radeon. In general we can't mix explicit options with menu entries with a
select.

Quoted 4 lines

I was trying that out. Removing DRM_KMS_FB_HELPER and having DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in
their respective xyz_fbdev.c files.

But with the stubbed out functions that should work, right? Why doesn't
it?

Quoted 8 lines

Quoted 4 lines

There are still calls to functions from fb core like fb_set_suspend and
register_framebuffer which aren't covered by the drm fb helper functions.

Hm, sounds like we need another patch to stub out fb_set_suspend when fbdev isn't enabled. Is there anything else?

There are a handful of fb core functions which are called by drm drivers:

fb_alloc_cmap/fb_dealloc_cmap

fb_sys_read/fb_sys_write

Quoted 8 lines

register_framebuffer/unregister_framebuffer/unlink_framebuffer/ remove_conflicting_framebuffers

fb_set_suspend

fb_deferred_io_init/fb_deferred_io_cleanup

framebuffer_alloc/framebuffer_release

Hm yeah that's somewhat annoying indeed. What about the following:
1. We move all the #include <linux/fb.h> from drivers into drm_fb_helper.h

2. Then we add stubs for these functions in drm_fb_helper.h, like this

#if defined(CONFIG_FB)
#include <linux/fb.h>
#else

Quoted 7 lines

/* static inline stubs for all the fb stuff used by kms drivers */ #endif

Imo this makes sense since kms drivers really have a bit a special situation with fbdev. They're not full-blown fbdev drivers and can be useful fully without fbdev.

I was trying this out. Removing 'linux/fb.h' and replacing stub fb funcs won't really work because struct declarations(like fb_info) also get removed.

I considered placing '#if IS_ENABLED(CONFIG_FB)' within linux/fb.h itself,
but that seemed a bit too intrusive.

This is what I'm currently doing:

- Some funcs, like framebufer_alloc/release, alloc_cmap/dealloc_cmap would
actually benefit if we have drm fb helpers for them. They are used in exactly the same manner by all the drivers.

- For the rest of the functions that are sparsely used, I was considering
making very simple drm_fb_* wrapper functions. Something like:

void drm_fb_helper_deferred_io_init(struct drm_fb_helper *helper)

Quoted 8 lines

{
        if (helper->fbdev)
                fb_deferred_io_init(helper->fbdev);
}

We could have all fb calls called within drm_fb_helper.c, creating drm_fb_helper_* stub functions would then be an easier task. What do you think?

That's actually an option I considered, but I hoped we could do it with less work. If this indeed works and you can create the patch that would be
awesome.

Thanks, Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project

Quoted 4 lines · Daniel Vetter

Quoted 3 lines · Archit Taneja

On 03/10/2015 03:17 PM, Daniel Vetter wrote:

Quoted 8 lines

Quoted 2 lines

Quoted 1 line · Archit Taneja

DRM_KMS_FB_HELPER selects that for us, right?

Hm right I've missed that. Reminds me that you need one more patch at the end to remove all the various select DRM_KMS_FB_HELPER from all drm drivers. Otherwise this knob here won't work by default if you e.g. select radeon. In general we can't mix explicit options with menu entries with a select.

I was trying that out. Removing DRM_KMS_FB_HELPER and having DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in their respective xyz_fbdev.c files.

Are you saying that we should remove DRM_KMS_FB_HELPER for such drivers and replace them with 'select DRM_FBDEV_EMULATION'?

Quoted 18 lines · Archit Taneja

Quoted 4 lines · Daniel Vetter

Quoted 3 lines · Archit Taneja

On 03/10/2015 03:17 PM, Daniel Vetter wrote:

Quoted 8 lines

Quoted 2 lines

Quoted 1 line · Archit Taneja

DRM_KMS_FB_HELPER selects that for us, right?

Hm right I've missed that. Reminds me that you need one more patch at the end to remove all the various select DRM_KMS_FB_HELPER from all drm drivers. Otherwise this knob here won't work by default if you e.g. select radeon. In general we can't mix explicit options with menu entries with a select.

I was trying that out. Removing DRM_KMS_FB_HELPER and having DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in their respective xyz_fbdev.c files.

Quoted 2 lines

Are you saying that we should remove DRM_KMS_FB_HELPER for such drivers and replace them with 'select DRM_FBDEV_EMULATION'?

Slightly tangential: As a rule of thumb, you should not "select" anything that is visible in menuconfig or has dependencies [1]. This will break the build eventually, and attempts to fix it are troublesome [2].

DRM_I915_FBDEV config is currently used to enable/disable fbdev emulation for the i915 kms driver.

Replace this with the top level DRM_FBDEV_EMULATION config option. Using this config lets us also prevent wrapping around drm_fb_helper_* calls with #ifdefs in certain places.

The #ifdef in drm_i915_private struct adding/removing members intel_fbdev and fbdev_suspend_work has been removed. This helps us use stub drm helper functions at not much cost.

Signed-off-by Archit Taneja <[email protected]>

---
 drivers/gpu/drm/i915/Kconfig         | 15 ---------------
 drivers/gpu/drm/i915/Makefile        |  4 ++--
 drivers/gpu/drm/i915/i915_debugfs.c  |  2 +-
 drivers/gpu/drm/i915/i915_drv.h      |  2 --
 drivers/gpu/drm/i915/intel_display.c | 10 ++++------
 drivers/gpu/drm/i915/intel_dp_mst.c  | 14 ++++++++------
 drivers/gpu/drm/i915/intel_drv.h     |  3 +--
 drivers/gpu/drm/i915/intel_fbdev.c   |  7 -------
 8 files changed, 16 insertions(+), 41 deletions(-)

drivers/gpu/drm/i915/Kconfig +0 -15

index 74acca9..bd9ccfc 100644
@@ -45,21 +45,6 @@ config DRM_I915_KMS
 
 	  If in doubt, say "Y".
 
-config DRM_I915_FBDEV
-	bool "Enable legacy fbdev support for the modesetting intel driver"
-	depends on DRM_I915
-	select DRM_KMS_FB_HELPER
-	select FB_CFB_FILLRECT
-	select FB_CFB_COPYAREA
-	select FB_CFB_IMAGEBLIT
-	default y
-	help
-	  Choose this option if you have a need for the legacy fbdev
-	  support. Note that this support also provide the linux console
-	  support on top of the intel modesetting driver.
-
-	  If in doubt, say "Y".
-
 config DRM_I915_PRELIMINARY_HW_SUPPORT
 	bool "Enable preliminary support for prerelease Intel hardware by default"
 	depends on DRM_I915

drivers/gpu/drm/i915/Makefile +2 -2

index f019225..3b3325d 100644
@@ -56,8 +56,8 @@ i915-y += intel_audio.o \
 	  intel_psr.o \
 	  intel_sideband.o \
 	  intel_sprite.o
-i915-$(CONFIG_ACPI)		+= intel_acpi.o intel_opregion.o
-i915-$(CONFIG_DRM_I915_FBDEV)	+= intel_fbdev.o
+i915-$(CONFIG_ACPI)			+= intel_acpi.o intel_opregion.o
+i915-$(CONFIG_DRM_FBDEV_EMULATION)	+= intel_fbdev.o
 
 # modesetting output/encoder code
 i915-y += dvo_ch7017.o \

drivers/gpu/drm/i915/i915_debugfs.c +1 -1

index e8b18e5..0c8bcd7 100644
@@ -1772,7 +1772,7 @@ static int i915_gem_framebuffer_info(struct seq_file *m, void *data)
 	struct intel_fbdev *ifbdev = NULL;
 	struct intel_framebuffer *fb;
 
-#ifdef CONFIG_DRM_I915_FBDEV
+#ifdef CONFIG_DRM_FBDEV_EMULATION
 	struct drm_i915_private *dev_priv = dev->dev_private;
 
 	ifbdev = dev_priv->fbdev;

drivers/gpu/drm/i915/i915_drv.h +0 -2

index 8727086..e511fa4 100644
@@ -1819,11 +1819,9 @@ struct drm_i915_private {
 
 	struct drm_i915_gem_object *vlv_pctx;
 
-#ifdef CONFIG_DRM_I915_FBDEV
 	/* list of fbdev register on this device */
 	struct intel_fbdev *fbdev;
 	struct work_struct fbdev_suspend_work;
-#endif
 
 	struct drm_property *broadcast_rgb_property;
 	struct drm_property *force_audio_property;

drivers/gpu/drm/i915/intel_display.c +0 -1

index e730789..9cf13e6 100644
@@ -8562,7 +8562,6 @@ static struct drm_framebuffer *
 mode_fits_in_fbdev(struct drm_device *dev,
 		   struct drm_display_mode *mode)
 {
-#ifdef CONFIG_DRM_I915_FBDEV
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct drm_i915_gem_object *obj;
 	struct drm_framebuffer *fb;

drivers/gpu/drm/i915/intel_display.c +4 -2

 }
 
 bool intel_get_load_detect_pipe(struct drm_connector *connector,

@@ -12807,11 +12803,13 @@ intel_user_framebuffer_create(struct drm_device *dev,
 	return intel_framebuffer_create(dev, mode_cmd, obj);
 }
 
-#ifndef CONFIG_DRM_I915_FBDEV
 static inline void intel_fbdev_output_poll_changed(struct drm_device *dev)
 {
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	if (dev_priv->fbdev)
+		drm_fb_helper_hotplug_event(&dev_priv->fbdev->helper);
 }
-#endif
 
 static const struct drm_mode_config_funcs intel_mode_funcs = {
 	.fb_create = intel_user_framebuffer_create,

drivers/gpu/drm/i915/intel_dp_mst.c +8 -6

index 9f67a37..fe69df0 100644
@@ -376,18 +376,20 @@ static bool intel_dp_mst_get_hw_state(struct intel_connector *connector)
 
 static void intel_connector_add_to_fbdev(struct intel_connector *connector)
 {
-#ifdef CONFIG_DRM_I915_FBDEV
 	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	drm_fb_helper_add_one_connector(&dev_priv->fbdev->helper, &connector->base);
-#endif
+
+	if (dev_priv->fbdev)
+		drm_fb_helper_add_one_connector(&dev_priv->fbdev->helper,
+			&connector->base);
 }
 
 static void intel_connector_remove_from_fbdev(struct intel_connector *connector)
 {
-#ifdef CONFIG_DRM_I915_FBDEV
 	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	drm_fb_helper_remove_one_connector(&dev_priv->fbdev->helper, &connector->base);
-#endif
+
+	if (dev_priv->fbdev)
+		drm_fb_helper_remove_one_connector(&dev_priv->fbdev->helper,
+			&connector->base);
 }
 
 static struct drm_connector *intel_dp_add_mst_connector(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port, const char *pathprop)

drivers/gpu/drm/i915/intel_drv.h +1 -2

index eef79cc..6920da2 100644
@@ -1062,12 +1062,11 @@ void intel_dvo_init(struct drm_device *dev);
 
 
 /* legacy fbdev emulation in intel_fbdev.c */
-#ifdef CONFIG_DRM_I915_FBDEV
+#ifdef CONFIG_DRM_FBDEV_EMULATION
 extern int intel_fbdev_init(struct drm_device *dev);
 extern void intel_fbdev_initial_config(void *data, async_cookie_t cookie);
 extern void intel_fbdev_fini(struct drm_device *dev);
 extern void intel_fbdev_set_suspend(struct drm_device *dev, int state, bool synchronous);
-extern void intel_fbdev_output_poll_changed(struct drm_device *dev);
 extern void intel_fbdev_restore_mode(struct drm_device *dev);
 #else
 static inline int intel_fbdev_init(struct drm_device *dev)

drivers/gpu/drm/i915/intel_fbdev.c +0 -7

index 3001a867..656ec1c 100644
@@ -762,13 +762,6 @@ void intel_fbdev_set_suspend(struct drm_device *dev, int state, bool synchronous
 	console_unlock();
 }
 
-void intel_fbdev_output_poll_changed(struct drm_device *dev)
-{
-	struct drm_i915_private *dev_priv = dev->dev_private;
-	if (dev_priv->fbdev)
-		drm_fb_helper_hotplug_event(&dev_priv->fbdev->helper);
-}
-
 void intel_fbdev_restore_mode(struct drm_device *dev)
 {
 	int ret;

Signature · 2 lines

The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

Quoted 108 lines · Archit Taneja

DRM_I915_FBDEV config is currently used to enable/disable fbdev emulation for the i915 kms driver.

Replace this with the top level DRM_FBDEV_EMULATION config option. Using this config lets us also prevent wrapping around drm_fb_helper_* calls with #ifdefs in certain places.

The #ifdef in drm_i915_private struct adding/removing members intel_fbdev and fbdev_suspend_work has been removed. This helps us use stub drm helper functions at not much cost.

Signed-off-by Archit Taneja <[email protected]>

---
  drivers/gpu/drm/i915/Kconfig         | 15 ---------------
  drivers/gpu/drm/i915/Makefile        |  4 ++--
  drivers/gpu/drm/i915/i915_debugfs.c  |  2 +-
  drivers/gpu/drm/i915/i915_drv.h      |  2 --
  drivers/gpu/drm/i915/intel_display.c | 10 ++++------
  drivers/gpu/drm/i915/intel_dp_mst.c  | 14 ++++++++------
  drivers/gpu/drm/i915/intel_drv.h     |  3 +--
  drivers/gpu/drm/i915/intel_fbdev.c   |  7 -------
  8 files changed, 16 insertions(+), 41 deletions(-)

drivers/gpu/drm/i915/Kconfig +0 -15

index 74acca9..bd9ccfc 100644
@@ -45,21 +45,6 @@ config DRM_I915_KMS
 
  	  If in doubt, say "Y".
 
-config DRM_I915_FBDEV
-	bool "Enable legacy fbdev support for the modesetting intel driver"
-	depends on DRM_I915
-	select DRM_KMS_FB_HELPER
-	select FB_CFB_FILLRECT
-	select FB_CFB_COPYAREA
-	select FB_CFB_IMAGEBLIT
-	default y
-	help
-	  Choose this option if you have a need for the legacy fbdev
-	  support. Note that this support also provide the linux console
-	  support on top of the intel modesetting driver.
-
-	  If in doubt, say "Y".
-
  config DRM_I915_PRELIMINARY_HW_SUPPORT
  	bool "Enable preliminary support for prerelease Intel hardware by default"
  	depends on DRM_I915

drivers/gpu/drm/i915/Makefile +2 -2

index f019225..3b3325d 100644
@@ -56,8 +56,8 @@ i915-y += intel_audio.o \
  	  intel_psr.o \
  	  intel_sideband.o \
  	  intel_sprite.o
-i915-$(CONFIG_ACPI)		+= intel_acpi.o intel_opregion.o
-i915-$(CONFIG_DRM_I915_FBDEV)	+= intel_fbdev.o
+i915-$(CONFIG_ACPI)			+= intel_acpi.o intel_opregion.o
+i915-$(CONFIG_DRM_FBDEV_EMULATION)	+= intel_fbdev.o
 
  # modesetting output/encoder code
  i915-y += dvo_ch7017.o \

drivers/gpu/drm/i915/i915_debugfs.c +1 -1

index e8b18e5..0c8bcd7 100644
@@ -1772,7 +1772,7 @@ static int i915_gem_framebuffer_info(struct seq_file *m, void *data)
  	struct intel_fbdev *ifbdev = NULL;
  	struct intel_framebuffer *fb;
 
-#ifdef CONFIG_DRM_I915_FBDEV
+#ifdef CONFIG_DRM_FBDEV_EMULATION
  	struct drm_i915_private *dev_priv = dev->dev_private;
 
  	ifbdev = dev_priv->fbdev;

drivers/gpu/drm/i915/i915_drv.h +0 -2

index 8727086..e511fa4 100644
@@ -1819,11 +1819,9 @@ struct drm_i915_private {
 
  	struct drm_i915_gem_object *vlv_pctx;
 
-#ifdef CONFIG_DRM_I915_FBDEV
  	/* list of fbdev register on this device */
  	struct intel_fbdev *fbdev;
  	struct work_struct fbdev_suspend_work;
-#endif
 
  	struct drm_property *broadcast_rgb_property;
  	struct drm_property *force_audio_property;

drivers/gpu/drm/i915/intel_display.c +0 -1

index e730789..9cf13e6 100644
@@ -8562,7 +8562,6 @@ static struct drm_framebuffer *
  mode_fits_in_fbdev(struct drm_device *dev,
  		   struct drm_display_mode *mode)
  {
-#ifdef CONFIG_DRM_I915_FBDEV
  	struct drm_i915_private *dev_priv = dev->dev_private;
  	struct drm_i915_gem_object *obj;
  	struct drm_framebuffer *fb;

@@ -8585,9 +8584,6 @@ mode_fits_in_fbdev(struct drm_device *dev,
  		return NULL;
 

drivers/gpu/drm/i915/intel_display.c mode_fits_in_fbdev(struct drm_device *dev, · line 8590

Quoted 4 lines

drivers/gpu/drm/i915/intel_display.c +0 -3

  	return fb;
-#else
-	return NULL;
-#endif

Won't this now blow up if there's no fbdev? Tbh I prefer a patch to just replace the CONFIG_ #define and then maybe a 2nd one on top to clean things up if you feel like. Same for the other changes in this patch.

DRM_IMX_FB_HELPER config is currently used to enable/disable fbdev emulation for the imx kms driver.

Remove this local config option and use the top level DRM_FBDEV_EMULATION config option where applicable. Using this config lets us also prevent wrapping around drm_fb_helper_* calls with #ifdefs in certain places.

We replace the #ifdef in imx_drm_driver_load with CONFIG_DRM_FBDEV_EMULATION. It's probably okay to get remove the #ifdef itself, but just left it here for now to be safe. It can be removed after some testing.

Signed-off-by Archit Taneja <[email protected]>

Hi Archit,

thanks for the cleanup!

Am Dienstag, den 10.03.2015, 15:11 +0530 schrieb Archit Taneja:

Quoted 7 lines

DRM_IMX_FB_HELPER config is currently used to enable/disable fbdev emulation for the imx kms driver.

Remove this local config option and use the top level DRM_FBDEV_EMULATION config option where applicable. Using this config lets us also prevent wrapping around drm_fb_helper_* calls with #ifdefs in certain places.

Quoted 5 lines

We replace the #ifdef in imx_drm_driver_load with CONFIG_DRM_FBDEV_EMULATION. It's probably okay to get remove the #ifdef itself, but just left it here for now to be safe. It can be removed after some testing.

Signed-off-by Archit Taneja <[email protected]>

Tested-by Philipp Zabel <[email protected]>

(Both with and without the #ifdef CONFIG_DRM_FBDEV_EMULATION removed.)

Although this is for another patch, I think the legacyfb_depth module_param should be removed altogether if CONFIG_DRM_FBDEV_EMULATION is disabled, so maybe that #ifdef should stay.

DRM_STI_FBDEV config is currently used to enable/disable fbdev emulation for
the sti kms driver.

Remove this local config option and use the top level DRM_FBDEV_EMULATION config
option instead where applicable.

We replace the #ifdef in sti_drm_load with CONFIG_DRM_FBDEV_EMULATION. It's probably okay to get remove the #ifdef itself, but just left it here for now to
be safe. It can be removed after some testing.

Signed-off-by Archit Taneja <[email protected]>

---
 drivers/gpu/drm/sti/Kconfig       | 6 ------
 drivers/gpu/drm/sti/sti_drm_drv.c | 2 +-
 2 files changed, 1 insertion(+), 7 deletions(-)

drivers/gpu/drm/sti/Kconfig +0 -3

index fbccc10..e3aa5af 100644
@@ -9,9 +9,3 @@ config DRM_STI
        select FW_LOADER_USER_HELPER_FALLBACK
        help
          Choose this option to enable DRM on STM stiH41x chipset
-
-config DRM_STI_FBDEV
-       bool "DRM frame buffer device for STMicroelectronics SoC stiH41x

Serie"

drivers/gpu/drm/sti/Kconfig +0 -3

-       depends on DRM_STI
-       help
-         Choose this option to enable FBDEV on top of DRM for STM stiH41x

chipset

drivers/gpu/drm/sti/sti_drm_drv.c +1 -1

index 5239fa1..90f121d 100644
@@ -76,7 +76,7 @@ static int sti_drm_load(struct drm_device *dev, unsigned
 long flags)
 
        drm_helper_disable_unused_functions(dev);
 
-#ifdef CONFIG_DRM_STI_FBDEV
+#ifdef CONFIG_DRM_FBDEV_EMULATION
        drm_fbdev_cma_init(dev, 32,
                   dev->mode_config.num_crtc,

                   dev->mode_config.num_connector);

--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation

Legacy fbdev emulation support via DRM is achieved through KMS FB helpers. Most modesetting drivers enable provide fbdev emulation by default by selecting KMS FB helpers. A few provide a separate Kconfig option for the user to enable or disbale fbdev emulation.

Enabling fbdev emulation is finally a distro-level decision. Having a top level Kconfig option for fbdev emulation helps by providing a uniform way to enable/disable fbdev emulation for any modesetting driver. It also lets us remove unnecessary driver specific Kconfig options that causes bloat.

With a top level Kconfig in place, we can stub out the fb helper functions when not needed without breaking functionality. Having stub functions also prevents drivers to require wrapping fb helper function calls with #ifdefs.

DRM_FBDEV_EMULATION defaults to y since many drivers enable fbdev emulation by default and majority of distributions expect the fbdev interface in the kernel.

Signed-off-by Archit Taneja <[email protected]>

---
 drivers/gpu/drm/Kconfig     |  12 +++
 drivers/gpu/drm/Makefile    |   2 +-
 include/drm/drm_fb_helper.h | 192 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 205 insertions(+), 1 deletion(-)

drivers/gpu/drm/Kconfig +1 -0

index e373f8a..8fd670b 100644
@@ -47,6 +47,18 @@ config DRM_KMS_FB_HELPER
 	help
 	  FBDEV helpers for KMS drivers.
 
+config DRM_FBDEV_EMULATION

drivers/gpu/drm/Kconfig +1 -0

+
 config DRM_LOAD_EDID_FIRMWARE
 	bool "Allow to specify an EDID data set instead of probing for it"
 	depends on DRM_KMS_HELPER

drivers/gpu/drm/Makefile +1 -1

index 5713d05..8858510 100644
@@ -23,7 +23,7 @@ drm-$(CONFIG_OF) += drm_of.o
 drm_kms_helper-y := drm_crtc_helper.o drm_dp_helper.o drm_probe_helper.o \
 		drm_plane_helper.o drm_dp_mst_topology.o drm_atomic_helper.o
 drm_kms_helper-$(CONFIG_DRM_LOAD_EDID_FIRMWARE) += drm_edid_load.o
-drm_kms_helper-$(CONFIG_DRM_KMS_FB_HELPER) += drm_fb_helper.o
+drm_kms_helper-$(CONFIG_DRM_FBDEV_EMULATION) += drm_fb_helper.o
 drm_kms_helper-$(CONFIG_DRM_KMS_CMA_HELPER) += drm_fb_cma_helper.o
 
 obj-$(CONFIG_DRM_KMS_HELPER) += drm_kms_helper.o

include/drm/drm_fb_helper.h +126 -0

index cc19e88..8f972da 100644
@@ -122,6 +122,7 @@ struct drm_fb_helper {
 	bool delayed_hotplug;
 };
 
+#ifdef CONFIG_DRM_FBDEV_EMULATION
 void drm_fb_helper_prepare(struct drm_device *dev, struct drm_fb_helper *helper,
 			   const struct drm_fb_helper_funcs *funcs);
 int drm_fb_helper_init(struct drm_device *dev,

@@ -188,4 +189,195 @@ drm_pick_cmdline_mode(struct drm_fb_helper_connector *fb_helper_conn,
 int drm_fb_helper_add_one_connector(struct drm_fb_helper *fb_helper, struct drm_connector *connector);
 int drm_fb_helper_remove_one_connector(struct drm_fb_helper *fb_helper,
 				       struct drm_connector *connector);
+#else
+static inline void drm_fb_helper_prepare(struct drm_device *dev,
+					struct drm_fb_helper *helper,
+					const struct drm_fb_helper_funcs *funcs)
+{
+}
+
+static inline int drm_fb_helper_init(struct drm_device *dev,
+		       struct drm_fb_helper *helper, int crtc_count,
+		       int max_conn)
+{
+	return 0;
+}
+
+static inline void drm_fb_helper_fini(struct drm_fb_helper *helper)
+{
+}
+
+static inline int drm_fb_helper_blank(int blank, struct fb_info *info)
+{
+	return 0;
+}
+
+static inline int drm_fb_helper_pan_display(struct fb_var_screeninfo *var,
+					    struct fb_info *info)
+{
+	return 0;
+}
+
+static inline int drm_fb_helper_set_par(struct fb_info *info)
+{
+	return 0;
+}
+
+static inline int drm_fb_helper_check_var(struct fb_var_screeninfo *var,
+					  struct fb_info *info)
+{
+	return 0;
+}
+
+static inline bool
+drm_fb_helper_restore_fbdev_mode_unlocked(struct drm_fb_helper *fb_helper)
+{
+	return true;
+}
+
+static inline struct fb_info *
+drm_fb_helper_alloc_fbi(struct drm_fb_helper *fb_helper)
+{
+	return NULL;
+}
+
+static inline void drm_fb_helper_unregister_fbi(struct drm_fb_helper *fb_helper)
+{
+}
+static inline void drm_fb_helper_release_fbi(struct drm_fb_helper *fb_helper)
+{
+}
+
+static inline void drm_fb_helper_fill_var(struct fb_info *info,
+					  struct drm_fb_helper *fb_helper,
+					  uint32_t fb_width, uint32_t fb_height)
+{
+}
+
+static inline void drm_fb_helper_fill_fix(struct fb_info *info, uint32_t pitch,
+					  uint32_t depth)
+{
+}
+
+static inline int drm_fb_helper_setcmap(struct fb_cmap *cmap,
+					struct fb_info *info)
+{
+	return 0;
+}
+
+static inline void drm_fb_helper_unlink_fbi(struct drm_fb_helper *fb_helper)
+{
+}
+
+static inline ssize_t drm_fb_helper_sys_read(struct fb_info *info,
+					char __user *buf, size_t count,
+					loff_t *ppos)
+{
+	return -ENODEV;
+}
+
+static inline ssize_t drm_fb_helper_sys_write(struct fb_info *info,
+					const char __user *buf, size_t count,
+					loff_t *ppos)
+{
+	return -ENODEV;
+}
+
+static inline void drm_fb_helper_sys_fillrect(struct fb_info *info,
+		const struct fb_fillrect *rect)
+{
+}
+
+static inline void drm_fb_helper_sys_copyarea(struct fb_info *info,
+		const struct fb_copyarea *area)
+{
+}
+
+static inline void drm_fb_helper_sys_imageblit(struct fb_info *info,
+		const struct fb_image *image)
+{
+}
+
+static inline void drm_fb_helper_cfb_fillrect(struct fb_info *info,
+		const struct fb_fillrect *rect)
+{
+}
+
+static inline void drm_fb_helper_cfb_copyarea(struct fb_info *info,
+		const struct fb_copyarea *area)
+{
+}
+
+static inline void drm_fb_helper_cfb_imageblit(struct fb_info *info,
+		const struct fb_image *image)
+{
+}
+
+static inline void drm_fb_helper_set_suspend(struct drm_fb_helper *fb_helper,

include/drm/drm_fb_helper.h +56 -0

+
+static inline int drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper)
+{
+	return 0;
+}
+
+static inline int drm_fb_helper_initial_config(struct drm_fb_helper *fb_helper,
+					       int bpp_sel)
+{
+	return 0;
+}
+
+static inline int
+drm_fb_helper_single_add_all_connectors(struct drm_fb_helper *fb_helper)
+{
+	return 0;
+}
+
+static inline int drm_fb_helper_debug_enter(struct fb_info *info)
+{
+	return 0;
+}
+
+static inline int drm_fb_helper_debug_leave(struct fb_info *info)
+{
+	return 0;
+}
+
+static inline struct drm_display_mode *
+drm_has_preferred_mode(struct drm_fb_helper_connector *fb_connector,
+		       int width, int height)
+{
+	return NULL;
+}
+
+static inline struct drm_display_mode *
+drm_pick_cmdline_mode(struct drm_fb_helper_connector *fb_helper_conn,
+		      int width, int height)
+{
+	return NULL;
+}
+
+static inline int
+drm_fb_helper_add_one_connector(struct drm_fb_helper *fb_helper,
+				struct drm_connector *connector)
+{
+	return 0;
+}
+
+static inline int
+drm_fb_helper_remove_one_connector(struct drm_fb_helper *fb_helper,
+				   struct drm_connector *connector)
+{
+	return 0;
+}
+#endif
 #endif

Signature · 2 lines

The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

DRM_I915_FBDEV config is currently used to enable/disable fbdev emulation for the i915 kms driver.

Replace this with the top level DRM_FBDEV_EMULATION config option. Using this config lets us also prevent wrapping around drm_fb_helper_* calls with

The #ifdef in drm_i915_private struct adding/removing members intel_fbdev and fbdev_suspend_work has been removed. This helps us use stub drm helper functions at not much cost.

Signed-off-by Archit Taneja <[email protected]>

---
 drivers/gpu/drm/i915/Kconfig         | 15 ---------------
 drivers/gpu/drm/i915/Makefile        |  4 ++--
 drivers/gpu/drm/i915/i915_debugfs.c  |  2 +-
 drivers/gpu/drm/i915/i915_drv.h      |  2 --
 drivers/gpu/drm/i915/intel_display.c | 10 ++++------
 drivers/gpu/drm/i915/intel_dp_mst.c  | 14 ++++++++------
 drivers/gpu/drm/i915/intel_drv.h     |  3 +--
 drivers/gpu/drm/i915/intel_fbdev.c   |  7 -------
 8 files changed, 16 insertions(+), 41 deletions(-)

drivers/gpu/drm/i915/Kconfig +0 -0

index 74acca9..bd9ccfc 100644

drivers/gpu/drm/i915/Kconfig +0 -8

-	default y
-	help
-	  Choose this option if you have a need for the legacy fbdev
-	  support. Note that this support also provide the linux console
-	  support on top of the intel modesetting driver.
-
-	  If in doubt, say "Y".
-
 config DRM_I915_PRELIMINARY_HW_SUPPORT
 	bool "Enable preliminary support for prerelease Intel hardware by default"
 	depends on DRM_I915

drivers/gpu/drm/i915/Makefile +2 -2

index b7ddf48..355e43f 100644
@@ -56,8 +56,8 @@ i915-y += intel_audio.o \
 	  intel_psr.o \
 	  intel_sideband.o \
 	  intel_sprite.o
-i915-$(CONFIG_ACPI)		+= intel_acpi.o intel_opregion.o
-i915-$(CONFIG_DRM_I915_FBDEV)	+= intel_fbdev.o
+i915-$(CONFIG_ACPI)			+= intel_acpi.o intel_opregion.o
+i915-$(CONFIG_DRM_FBDEV_EMULATION)	+= intel_fbdev.o
 
 # modesetting output/encoder code
 i915-y += dvo_ch7017.o \

drivers/gpu/drm/i915/i915_debugfs.c +1 -1

index 82bbe3f..bcce317 100644
@@ -1849,7 +1849,7 @@ static int i915_gem_framebuffer_info(struct seq_file *m, void *data)
 	struct intel_fbdev *ifbdev = NULL;
 	struct intel_framebuffer *fb;
 
-#ifdef CONFIG_DRM_I915_FBDEV
+#ifdef CONFIG_DRM_FBDEV_EMULATION
 	struct drm_i915_private *dev_priv = dev->dev_private;
 
 	ifbdev = dev_priv->fbdev;

drivers/gpu/drm/i915/i915_drv.h +0 -0

index 542fac6..ab5881c 100644

drivers/gpu/drm/i915/i915_drv.h +0 -1

 	/* list of fbdev register on this device */
 	struct intel_fbdev *fbdev;
 	struct work_struct fbdev_suspend_work;
-#endif
 
 	struct drm_property *broadcast_rgb_property;
 	struct drm_property *force_audio_property;

drivers/gpu/drm/i915/intel_display.c +4 -6

index 1b61f98..0acd801 100644
@@ -9886,7 +9886,6 @@ static struct drm_framebuffer *
 mode_fits_in_fbdev(struct drm_device *dev,
 		   struct drm_display_mode *mode)
 {
-#ifdef CONFIG_DRM_I915_FBDEV
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct drm_i915_gem_object *obj;
 	struct drm_framebuffer *fb;

@@ -9909,9 +9908,6 @@ mode_fits_in_fbdev(struct drm_device *dev,
 		return NULL;
 
 	return fb;
-#else
-	return NULL;
-#endif
 }
 
 static int intel_modeset_setup_plane_state(struct drm_atomic_state *state,

@@ -14296,11 +14292,13 @@ intel_user_framebuffer_create(struct drm_device *dev,
 	return intel_framebuffer_create(dev, mode_cmd, obj);
 }
 
-#ifndef CONFIG_DRM_I915_FBDEV
 static inline void intel_fbdev_output_poll_changed(struct drm_device *dev)
 {
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	if (dev_priv->fbdev)
+		drm_fb_helper_hotplug_event(&dev_priv->fbdev->helper);
 }
-#endif
 
 static const struct drm_mode_config_funcs intel_mode_funcs = {
 	.fb_create = intel_user_framebuffer_create,

drivers/gpu/drm/i915/intel_dp_mst.c +8 -6

index 6e4cc53..66eaf6f 100644
@@ -395,18 +395,20 @@ static bool intel_dp_mst_get_hw_state(struct intel_connector *connector)
 
 static void intel_connector_add_to_fbdev(struct intel_connector *connector)
 {
-#ifdef CONFIG_DRM_I915_FBDEV
 	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	drm_fb_helper_add_one_connector(&dev_priv->fbdev->helper, &connector->base);
-#endif
+
+	if (dev_priv->fbdev)
+		drm_fb_helper_add_one_connector(&dev_priv->fbdev->helper,
+			&connector->base);
 }
 
 static void intel_connector_remove_from_fbdev(struct intel_connector *connector)
 {
-#ifdef CONFIG_DRM_I915_FBDEV
 	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
-	drm_fb_helper_remove_one_connector(&dev_priv->fbdev->helper, &connector->base);
-#endif
+
+	if (dev_priv->fbdev)
+		drm_fb_helper_remove_one_connector(&dev_priv->fbdev->helper,
+			&connector->base);
 }
 
 static struct drm_connector *intel_dp_add_mst_connector(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port, const char *pathprop)

drivers/gpu/drm/i915/intel_drv.h +1 -2

index 1059283..371b201 100644
@@ -1207,12 +1207,11 @@ void intel_dvo_init(struct drm_device *dev);
 
 
 /* legacy fbdev emulation in intel_fbdev.c */
-#ifdef CONFIG_DRM_I915_FBDEV
+#ifdef CONFIG_DRM_FBDEV_EMULATION
 extern int intel_fbdev_init(struct drm_device *dev);
 extern void intel_fbdev_initial_config(void *data, async_cookie_t cookie);
 extern void intel_fbdev_fini(struct drm_device *dev);
 extern void intel_fbdev_set_suspend(struct drm_device *dev, int state, bool synchronous);
-extern void intel_fbdev_output_poll_changed(struct drm_device *dev);
 extern void intel_fbdev_restore_mode(struct drm_device *dev);
 #else
 static inline int intel_fbdev_init(struct drm_device *dev)

drivers/gpu/drm/i915/intel_fbdev.c +0 -7

index 4aa21f7..445c35f 100644
@@ -798,13 +798,6 @@ void intel_fbdev_set_suspend(struct drm_device *dev, int state, bool synchronous
 	console_unlock();
 }
 
-void intel_fbdev_output_poll_changed(struct drm_device *dev)
-{
-	struct drm_i915_private *dev_priv = dev->dev_private;
-	if (dev_priv->fbdev)
-		drm_fb_helper_hotplug_event(&dev_priv->fbdev->helper);
-}
-
 void intel_fbdev_restore_mode(struct drm_device *dev)
 {
 	int ret;

Signature · 2 lines

The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation