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

[Kandpal, Suraj]

> -----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