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

[Garg, Nemesa]

> -----Original Message-----
> From: Pottumuttu, Sai Teja <sai.teja.pottumuttu at intel.com>
> Sent: Thursday, October 17, 2024 10:24 PM
> To: Kandpal, Suraj <suraj.kandpal at intel.com>; Garg, Nemesa
> <nemesa.garg at intel.com>; intel-xe at lists.freedesktop.org
> Cc: Roper, Matthew D <matthew.d.roper at intel.com>
> Subject: Re: [PATCH] drm/i915/display: Workaround for odd panning for planar
> yuv
> 
> 
> On 17-10-2024 13:35, Kandpal, Suraj wrote:
> >
> >> -----Original Message-----
> >> From: Intel-xe <intel-xe-bounces at lists.freedesktop.org> On Behalf Of
> >> Nemesa Garg
> >> Sent: Wednesday, October 16, 2024 12:55 PM
> >> To: intel-xe at lists.freedesktop.org
> >> Cc: Garg, Nemesa <nemesa.garg at intel.com>
> >> Subject: [PATCH] drm/i915/display: Workaround for odd panning for
> >> planar yuv
> >>
> >> Disable the support for odd x pan for even xsize for NV12 format as
> >> underrun issue is seen.
> 
> - Probably with the discussion and the latest update to the patch we should also
> update the commit message to aptly reflect what are we doing here. (We can
> remove even xsize part or maybe give more explanation on why even x size is not
> being checked in the patch)
> 
> - We should ideally be using the workaround lineage number in the commit
> message.
> 
Sure. 
> - Also, seems like NV12 is not the only planar format, should we check for a planar
> format in general instead of NV12 specifically?
> Cc: Matt Roper
> 
In WA its mentioned that the issue is seen for YUV420 format so that's why I'm checking for NV12 format.

Thanks,
Nemesa

> Thanks
> Sai Teja
> 
> >>
> >> WA: 16024459452
> > This should be right above your signed-off-by The rest LGTM,
> > Reviewed-by: Suraj Kandpal <suraj.kandpal at intel.com>
> >
> >> v2: Replace HSD with WA in commit message [Suraj]
> >>      Modified the condition for handling odd panning
> >>
> >> v3: Simplified the condition for checking hsub
> >>      Using older framework for wa as rev1[Jani]
> >>
> >> v4: Modify the condition for hsub [Sai Teja]
> >>      Initialize hsub in else path [Dan]
> >>
> >> v5: Replace IS_LUNARLAKE with display version.
> >>      Resolve nitpicks[Jani]
> >>
> >> v6: Replace -EINVAL with hsub [Suraj]
> >>      Remove src_w check as not required
> >>
> >> Signed-off-by: Nemesa Garg <nemesa.garg at intel.com>
> >> ---
> >>   drivers/gpu/drm/i915/display/intel_atomic_plane.c | 5 +++++
> >>   1 file changed, 5 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..2d7ca6e62926 100644
> >> --- a/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> >> +++ b/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> >> @@ -1031,6 +1031,11 @@ int intel_plane_check_src_coordinates(struct
> >> intel_plane_state *plane_state)
> >>   		 */
> >>   		hsub = 1;
> >>   		vsub = 1;
> >> +
> >> +		/* Wa_16023981245 */
> >> +		if (DISPLAY_VER(i915) == 20 && fb->format->format ==
> >> DRM_FORMAT_NV12 &&
> >> +		    src_x % 2 != 0)
> >> +			hsub = 2;
> >>   	} else {
> >>   		hsub = fb->format->hsub;
> >>   		vsub = fb->format->vsub;
> >> --
> >> 2.25.1