[Intel-gfx] [PATCH xf86-video-intel] sna/uxa: Fix colormap handling at screen depth 30. (v2)

[Chris Wilson]

Quoting Mario Kleiner (2019-01-20 19:45:18)
> On Mon, Oct 15, 2018 at 6:21 PM Ville Syrjälä <ville.syrjala at linux.intel.com>
> wrote:
> 
>     On Tue, Jun 12, 2018 at 06:20:35PM +0200, Mario Kleiner wrote:
>     > The various clut handling functions like a setup
>     > consistent with the x-screen color depth. Otherwise
>     > we observe improper sampling in the gamma tables
>     > at depth 30.
>     >
>     > Therefore replace hard-coded bitsPerRGB = 8 by actual
>     > bits per channel scrn->rgbBits. Also use this for call
>     > to xf86HandleColormaps().
>     >
>     > Tested for uxa and sna at depths 8, 16, 24 and 30 on
>     > IvyBridge, and tested at depth 24 and 30 that xgamma
>     > and gamma table animations work, and with measurement
>     > equipment to make sure identity gamma ramps actually
>     > are identity mappings at the output.
>     >
>     > v2: Also deal with X-Server 1.19 and earlier, which as of
>     >     v1.19.6 lack a fix to color palette handling and can
>     >     not deal with depths/bpc > 24/8 bpc. On < 1.20 we skip
>     >     xf86HandleColormaps() setup at > 8 bpc. This disables
>     >     color palette handling on such servers at > 8 bpc, but
>     >     still keeps RandR gamma table handling intact.
>     >
>     >     Tested on 1.19.6 and 1.20.0 to do the right thing.
>     >
>     > Signed-off-by: Mario Kleiner <mario.kleiner.de at gmail.com>
> 
>     Forgot this didn't get applied. It did make sense to me at the
>     time when I was looking at the explosions with depth 30.
>     Still seems to do the trick on 1.19, and redshit still works
>     so
> 
>     Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> 
> 
> Thanks Ville!
> 
> Now it just needs to get merged, please. Chris?

Pushed, thanks for the reminder.
-Chris