Patch "drm/nouveau: prefer XBGR2101010 for addfb ioctl" has been added to the 4.14-stable tree

This is a note to let you know that I've just added the patch titled

drm/nouveau: prefer XBGR2101010 for addfb ioctl

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:

     drm-nouveau-prefer-xbgr2101010-for-addfb-ioctl.patch

and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Ilia Mirkin <[email protected]>
Date: Sat, 3 Feb 2018 14:11:23 -0500
Subject: drm/nouveau: prefer XBGR2101010 for addfb ioctl

From: Ilia Mirkin <[email protected]>

commit c20bb155c2c5acb775f68be5d84fe679687c3c1e upstream.

Nouveau only exposes support for XBGR2101010. Prior to the atomic conversion, drm would pass in the wrong format in the framebuffer, but it was always ignored -- both userspace (xf86-video-nouveau) and the kernel driver agreed on the layout, so the fact that the format was wrong didn't matter.

With the atomic conversion, nouveau all of a sudden started caring about the exact format, and so the previously-working code in xf86-video-nouveau no longer functioned since the (internally-assigned) format from the addfb ioctl was wrong.

This change adds infrastructure to allow a drm driver to specify that it prefers the XBGR format variant for the addfb ioctl, and makes nouveau's nv50 display driver set it. (Prior gens had no support for 30bpp at all.)

---
 drivers/gpu/drm/drm_framebuffer.c      |    4 ++++
 drivers/gpu/drm/nouveau/nv50_display.c |    1 +
 include/drm/drm_drv.h                  |    1 +
 3 files changed, 6 insertions(+)

@@ -118,6 +118,10 @@ int drm_mode_addfb(struct drm_device *de
 	r.pixel_format = drm_mode_legacy_fb_format(or->bpp, or->depth);
 	r.handles[0] = or->handle;
 
+	if (r.pixel_format == DRM_FORMAT_XRGB2101010 &&
+	    dev->driver->driver_features & DRIVER_PREFER_XBGR_30BPP)
+		r.pixel_format = DRM_FORMAT_XBGR2101010;
+
 	ret = drm_mode_addfb2(dev, &r, file_priv);
 	if (ret)
 		return ret;

@@ -4426,6 +4426,7 @@ nv50_display_create(struct drm_device *d
 	nouveau_display(dev)->fini = nv50_display_fini;
 	disp->disp = &nouveau_display(dev)->disp;
 	dev->mode_config.funcs = &nv50_disp_func;
+	dev->driver->driver_features |= DRIVER_PREFER_XBGR_30BPP;
 	if (nouveau_atomic)
 		dev->driver->driver_features |= DRIVER_ATOMIC;
 

@@ -55,6 +55,7 @@ struct drm_mode_create_dumb;
 #define DRIVER_ATOMIC			0x10000
 #define DRIVER_KMS_LEGACY_CONTEXT	0x20000
 #define DRIVER_SYNCOBJ                  0x40000
+#define DRIVER_PREFER_XBGR_30BPP        0x80000
 
 /**
  * struct drm_driver - DRM driver structure

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/drm-nouveau-prefer-xbgr2101010-for-addfb-ioctl.patch