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

From: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
To: Mario Kleiner <mario.kleiner.de@gmail.com>
Cc: intel-gfx <intel-gfx@lists.freedesktop.org>
Subject: Re: [PATCH xf86-video-intel] sna/uxa: Fix colormap handling at screen depth 30. (v2)
Date: Mon, 21 Jan 2019 16:54:37 +0200	[thread overview]
Message-ID: <20190121145437.GN20097@intel.com> (raw)
In-Reply-To: <CAEsyxyj+k3xv2kek4nSN1ntoTGqcaOVnbwiYiVRZ3PvvA0fVBw@mail.gmail.com>

On Sun, Jan 20, 2019 at 08:45:18PM +0100, Mario Kleiner wrote:
> On Mon, Oct 15, 2018 at 6:21 PM Ville Syrjälä <ville.syrjala@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@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@linux.intel.com>
> >
> >
> Thanks Ville!
> 
> Now it just needs to get merged, please. Chris?
> 
> One last missing piece is support for 1024 slot gamma tables in i965-kms,
> or gamma table bypass for such high bit depth framebuffers to make them
> actually useful. Ville, i think you mentioned working on that around spring
> last year?

Kernel bits for gamma table bypass are on the list:
https://patchwork.freedesktop.org/series/55081/

Apart from that I've not had any real time to work on it.

-- 
Ville Syrjälä
Intel
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