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

[Kandpal, Suraj]

> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf Of
> Nemesa Garg
> Sent: Monday, September 30, 2024 4:54 PM
> To: intel-gfx 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.
> 
> WA: 16024459452
> 
> 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]
> 
> 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..e3401a4f7992 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.
> +		 *  Do not support odd x-panning for even xsize for NV12.
> +		 */
> +		if (DISPLAY_VER(i915) == 20 && fb->format->format ==
> DRM_FORMAT_NV12 &&
> +		    src_x % 2 != 0 && src_w % 2 == 0)

Also one more issue here according to HSD " Odd Pan position  + Even plane size for YVU420 ..... SW decision is to not allow Odd Pan X position"
Which would mean you need to check src_w and src_h instead of src_x to check even plane.

Regards,
Suraj Kandpal
> +			return -EINVAL;
> +
>  		hsub = 1;
>  		vsub = 1;
>  	} else {
> --
> 2.25.1