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

[Pottumuttu, Sai Teja]

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.

- 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

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