[PATCH] drm/i915/display: Workaround for odd panning for planar yuv

[Kandpal, Suraj]

> -----Original Message-----
> From: Kandpal, Suraj
> Sent: Wednesday, July 24, 2024 10:32 PM
> To: Nemesa Garg <nemesa.garg at intel.com>; intel-xe at lists.freedesktop.org
> Cc: Heikkila, Juha-pekka <juha-pekka.heikkila at intel.com>; Shankar, Uma
> <uma.shankar at intel.com>; Garg, Nemesa <Nemesa.Garg at intel.com>
> Subject: RE: [PATCH] drm/i915/display: Workaround for odd panning for
> planar yuv
> 
> 
> 
> > -----Original Message-----
> > From: Intel-xe <intel-xe-bounces at lists.freedesktop.org> On Behalf Of
> > Nemesa Garg
> > Sent: Wednesday, July 24, 2024 6:36 PM
> > To: intel-xe at lists.freedesktop.org
> > Cc: Heikkila, Juha-pekka <juha-pekka.heikkila at intel.com>; Shankar, Uma
> > <uma.shankar at intel.com>; Garg, Nemesa <nemesa.garg at intel.com>
> > Subject: [PATCH] drm/i915/display: Workaround for odd panning for
> > planar yuv
> >
> > Underrun/corruption issue is seen for NV12 format for odd panning on
> > LNL due to hardware bug.
> > Disable the format.
> 
> When describing the commit for a WA no need to mention what the issue is
> that is described In the WA number only describe what the patch is doing.
> 
> >
> > HSD: 16024459452
> 
> Better to write this as
> WA: 16024459452
> >
> > Signed-off-by: Nemesa Garg <nemesa.garg at intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_atomic_plane.c | 8 ++++++++
> >  1 file changed, 8 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> > b/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> > index e979786aa5cf..f927e6a0b28b 100644
> > --- a/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> > +++ b/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> > @@ -1029,6 +1029,14 @@ int intel_plane_check_src_coordinates(struct
> > intel_plane_state *plane_state)
> >  		 * This allows NV12 and P0xx formats to have odd size
> and/or odd
> >  		 * source coordinates on DISPLAY_VER(i915) >= 20
> >  		 */
> > +
> > +		/*
> > +		 * Wa_16023981245 for display version 20.
> > +		 * Disable odd pan for NV12 format.
> > +		 */
> > +		if (DISPLAY_VER(i915) == 20 && fb->format->format ==
> > DRM_FORMAT_NV12)
> > +			return 0;
> 
> Also is this the correct implementation of this WA it says to disallow odd
> xpan and disable even xsize I don't See xsize implementation anywhere.
> Next is if we disable odd xpan shouldn't we then program it to allow even
> xpan this returns without doing anything
> 
> Regards,
> Suraj Kandpal
> > +
> >  		hsub = 1;
> >  		vsub = 1;
> >  	} else {
> > --
> > 2.25.1