On Mon, Feb 05, 2018 at 09:10:12AM -0500, Ilia Mirkin wrote: > On Mon, Feb 5, 2018 at 8:58 AM, Ville Syrjälä > <ville.syrjala@xxxxxxxxxxxxxxx> wrote: > > On Sat, Feb 03, 2018 at 02:11:23PM -0500, Ilia Mirkin wrote: > >> 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.) > >> > >> Signed-off-by: Ilia Mirkin <imirkin@xxxxxxxxxxxx> > >> Cc: stable@xxxxxxxxxxxxxxx # v4.10+ > >> --- > >> > >> Wasn't sure if the nouveau line needs to be split out into a separate > >> change or not. > >> > >> 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(+) > >> > >> diff --git a/drivers/gpu/drm/drm_framebuffer.c b/drivers/gpu/drm/drm_framebuffer.c > >> index 5a13ff29f4f0..c0530a1af5e3 100644 > >> --- a/drivers/gpu/drm/drm_framebuffer.c > >> +++ b/drivers/gpu/drm/drm_framebuffer.c > >> @@ -121,6 +121,10 @@ int drm_mode_addfb(struct drm_device *dev, > >> 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; > > > > I think I'd much prefer if the driver just passed some kind of a > > bpp/depth->format mapping table to the core, or maybe an optional > > vfunc to allow the driver to override drm_mode_legacy_fb_format() > > behaviour. > > > > drm_mode_legacy_fb_format() is called from the fbdev setup as well > > so handling this only in addfb doesn't look sufficient. > > Well, in practice fbdev won't pick a 30bpp mode. But I get the point. > It would also enable a driver to have a funky RGB ordering for depth > 24/32 and others. Although I don't know if there are any customers for > that in practice. > > A vfunc works for me. > > Anyone else want to opine before I go for it? I'm happy to do the > work, but want to make sure I'm not just doing things that'll get > rejected, as I have a limited amount of time to do these things. Imo the very obvious hack is totally fine, makes it stick out more that we have a fairly nasty uapi inconsistency here. Also vfunc or explicit table open up the door for even more driver abuse in the future, which I don't like. vfunc for 1 case ever is also overkill. Wrt fbdev: Linus seems to have volunteered to switch fbdev from depth/bpp to explicit pixel formats, so no worries. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
