drm/fb: avoid sleeping in unblank_screen() if oops in progress
Subsystems (2)
PATCH 1/1 drm/fb: avoid sleeping in unblank_screen() if oops in progress
unblank_screen() can be called from interrupt context during oops. thus all ->fb_blank handlers should avoid sleeping in this situation.
callstack:panic()bust_spinlocks(1)unblank_screen()vc->vc_sw->con_blank()fbcon_blank()fb_blank()info->fbops->fb_blank()drm_fb_helper_blank()drm_fb_helper_dpms()mutex_lock(&dev->mode_config.mutex)
Signed-off-by Konstantin Khlebnikov <[email protected]>
Cc Andrew Morton <[email protected]>
Cc David Airlie <[email protected]>
--- drivers/gpu/drm/drm_fb_helper.c | 25 +++++++++++++------------ 1 file changed, 13 insertions(+), 12 deletions(-)
drivers/gpu/drm/drm_fb_helper.c +13 -12
@@ -326,7 +326,7 @@ static struct sysrq_key_op sysrq_drm_fb_helper_restore_op = {static struct sysrq_key_op sysrq_drm_fb_helper_restore_op = { };#endif -static void drm_fb_helper_dpms (struct fb_info *info,int dpms_mode) +static int drm_fb_helper_dpms (struct fb_info *info,int dpms_mode) {struct drm_fb_helper *fb_helper = info->par;struct drm_device *dev = fb_helper->dev;
@@ -334,10 +334,15 @@ static void drm_fb_helper_dpms(struct fb_info *info, int dpms_mode)struct drm_connector *connector;int i, j; +if (oops_in_progress) { +if (!mutex_trylock (&dev->mode_config.mutex)) +return -EBUSY ; + }else +mutex_lock (&dev->mode_config.mutex); +/* * For each CRTC in this fb, turn the connectors on/off. */ -mutex_lock (&dev->mode_config.mutex);for (i =0 ; i < fb_helper->crtc_count; i++) { crtc = fb_helper->crtc_info[i].mode_set.crtc;
@@ -353,6 +358,7 @@ static void drm_fb_helper_dpms(struct fb_info *info, int dpms_mode) } }mutex_unlock (&dev->mode_config.mutex); +return 0 ; }int drm_fb_helper_blank (int blank,struct fb_info *info)
@@ -360,24 +366,19 @@ int drm_fb_helper_blank(int blank, struct fb_info *info)switch (blank) {/* Display: On; HSync: On, VSync: On */ case FB_BLANK_UNBLANK : -drm_fb_helper_dpms (info,DRM_MODE_DPMS_ON ); -break ; +return drm_fb_helper_dpms (info,DRM_MODE_DPMS_ON );/* Display: Off; HSync: On, VSync: On */ case FB_BLANK_NORMAL : -drm_fb_helper_dpms (info,DRM_MODE_DPMS_STANDBY ); -break ; +return drm_fb_helper_dpms (info,DRM_MODE_DPMS_STANDBY );/* Display: Off; HSync: Off, VSync: On */ case FB_BLANK_HSYNC_SUSPEND : -drm_fb_helper_dpms (info,DRM_MODE_DPMS_STANDBY ); -break ; +return drm_fb_helper_dpms (info,DRM_MODE_DPMS_STANDBY );/* Display: Off; HSync: On, VSync: Off */ case FB_BLANK_VSYNC_SUSPEND : -drm_fb_helper_dpms (info,DRM_MODE_DPMS_SUSPEND ); -break ; +return drm_fb_helper_dpms (info,DRM_MODE_DPMS_SUSPEND );/* Display: Off; HSync: Off, VSync: Off */ case FB_BLANK_POWERDOWN : -drm_fb_helper_dpms (info,DRM_MODE_DPMS_OFF ); -break ; +return drm_fb_helper_dpms (info,DRM_MODE_DPMS_OFF ); }return 0 ; }
Quoted 15 lines · Konstantin Khlebnikov
unblank_screen()can be called from interrupt context during oops. thus all ->fb_blank handlers should avoid sleeping in this situation.callstack:
panic()bust_spinlocks(1)unblank_screen()vc->vc_sw->con_blank()fbcon_blank()fb_blank()info->fbops->fb_blank()drm_fb_helper_blank()drm_fb_helper_dpms()mutex_lock(&dev->mode_config.mutex)
Quoted 4 lines
Signed-off-by Konstantin Khlebnikov <[email protected]>Cc Andrew Morton <[email protected]>Cc David Airlie <[email protected]>
Since the fb helper already has its own panic notifier it's imo better to just bail out if there's an oops in progress. The panic notifier itself completely lacks locking though. I'm working on some fb helper cleanups, so I'll take care of this mess.
-Daniel
Quoted 77 lines
--- drivers/gpu/drm/drm_fb_helper.c | 25 +++++++++++++------------ 1 file changed, 13 insertions(+), 12 deletions(-)drivers/gpu/drm/drm_fb_helper.c +13
-12@@ -326,7 +326,7 @@ static struct sysrq_key_op sysrq_drm_fb_helper_restore_op = {static struct sysrq_key_op sysrq_drm_fb_helper_restore_op = { };#endif -static void drm_fb_helper_dpms (struct fb_info *info,int dpms_mode) +static int drm_fb_helper_dpms (struct fb_info *info,int dpms_mode) {struct drm_fb_helper *fb_helper = info->par;struct drm_device *dev = fb_helper->dev;@@ -334,10 +334,15 @@ static void drm_fb_helper_dpms(struct fb_info *info, int dpms_mode)struct drm_connector *connector;int i, j; +if (oops_in_progress) { +if (!mutex_trylock (&dev->mode_config.mutex)) +return -EBUSY ; + }else +mutex_lock (&dev->mode_config.mutex); +/* * For each CRTC in this fb, turn the connectors on/off. */ -mutex_lock (&dev->mode_config.mutex);for (i =0 ; i < fb_helper->crtc_count; i++) { crtc = fb_helper->crtc_info[i].mode_set.crtc;@@ -353,6 +358,7 @@ static void drm_fb_helper_dpms(struct fb_info *info, int dpms_mode) } }mutex_unlock (&dev->mode_config.mutex); +return 0 ; }int drm_fb_helper_blank (int blank,struct fb_info *info)@@ -360,24 +366,19 @@ int drm_fb_helper_blank(int blank, struct fb_info *info)switch (blank) {/* Display: On; HSync: On, VSync: On */ case FB_BLANK_UNBLANK : -drm_fb_helper_dpms (info,DRM_MODE_DPMS_ON ); -break ; +return drm_fb_helper_dpms (info,DRM_MODE_DPMS_ON );/* Display: Off; HSync: On, VSync: On */ case FB_BLANK_NORMAL : -drm_fb_helper_dpms (info,DRM_MODE_DPMS_STANDBY ); -break ; +return drm_fb_helper_dpms (info,DRM_MODE_DPMS_STANDBY );/* Display: Off; HSync: Off, VSync: On */ case FB_BLANK_HSYNC_SUSPEND : -drm_fb_helper_dpms (info,DRM_MODE_DPMS_STANDBY ); -break ; +return drm_fb_helper_dpms (info,DRM_MODE_DPMS_STANDBY );/* Display: Off; HSync: On, VSync: Off */ case FB_BLANK_VSYNC_SUSPEND : -drm_fb_helper_dpms (info,DRM_MODE_DPMS_SUSPEND ); -break ; +return drm_fb_helper_dpms (info,DRM_MODE_DPMS_SUSPEND );/* Display: Off; HSync: Off, VSync: Off */ case FB_BLANK_POWERDOWN : -drm_fb_helper_dpms (info,DRM_MODE_DPMS_OFF ); -break ; +return drm_fb_helper_dpms (info,DRM_MODE_DPMS_OFF ); }return 0 ; }_______________________________________________
dri-devel mailing list
[email protected]
http://lists.freedesktop.org/mailman/listinfo/dri-devel
Signature · 3 lines
Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch