[Intel-gfx] [PATCH v2] drm/i915/hsw: keep gamma and CSC enabled for primary plane disable

[Bob Paauwe]

On Thu, 15 Oct 2015 15:41:30 +0300
Ville Syrjälä <ville.syrjala at linux.intel.com> wrote:

> On Thu, Oct 15, 2015 at 02:31:09PM +0200, Daniel Vetter wrote:
> > 
> > On Thu, Oct 15, 2015 at 12:51 AM, Kevin Strasser <kevin.strasser at linux.intel.com> wrote:
> > > On HSW the crc differs between black and disabled primary planes, causing an
> > > assert to fail in the kms_universal_plane test. It seems that gamma correction
> > > and color space conversion are causing the black primary plane case to result in
> > > a brighter color than the disabled primary plane case.
> > >
> > > Keep gamma and CSC bits enabled for plane disable path on HSW.
> > >
> > > v2: Avoid use of RMW
> > >     Keep path unchanged for non-HSW users
> > >
> > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=89331
> > > Testcase: igt/kms_universal_plane/universal-plane-pipe-A-functional
> > > Signed-off-by: Kevin Strasser <kevin.strasser at linux.intel.com>
> > 
> > With big discussions please add everyone who participated (Ville, Chris,
> > Jani, me) to the cc list of the sob section of the patch when doing a new
> > revisions.
> > 
> > Bob did something eerily similarly a while ago to fix crc failures:
> > 
> > http://lists.freedesktop.org/archives/intel-gfx/2015-August/074657.html
> > http://lists.freedesktop.org/archives/intel-gfx/2015-August/074828.html
> > 
> > Unfortunately those patches did go nowhere :( Related?
> 
> Those seem to be for active plane cases. I'll go review them...
> 

I've been looking at the same test case failure on BXT. The bxt/skl
update primary plane function is similar to HSW's in that it was
clearing the gamma and csc bits when the plane was disabled. So I first
tried the same fix but it didn't work.  Matt and I were discussing this
and thought it might be the background (PIPE_BOTTOM_COLOR) that was
causing the CRC failures.  And yes, it is.  The PIPE_BOTTOM_COLOR also
has gamma and csc enable bits which default to off.  If those are
flipped on, then the CRC's match between a disabled plane and a black
plane. 

So it seems to make CRC's match we need to make sure that all planes
(primary/sprite/cursor/bottom) have the same gamma/csc settings.

Chandra had a patch that adds a property for bottom color a while back
but it seems to have stalled. 

http://lists.freedesktop.org/archives/intel-gfx/2015-June/069836.html

-- 
--
Bob Paauwe                  
Bob.J.Paauwe at intel.com
IOTG / PED Software Organization
Intel Corp.  Folsom, CA
(916) 356-6193