[PATCH] drm/amd/display: reject both non-zero src_x and src_y only for DCN1x

[S, Shirish]

Hi Paul,

On 11/8/2021 7:51 PM, Paul Menzel wrote:
> [Which address should be used: sshankar at amd.com or shirish.s at amd.com?]
"shirish.s at amd.com"
>
> Dear Shirish,
>
>
> Am 08.11.21 um 12:11 schrieb S, Shirish:
>
>> On 11/8/2021 2:25 PM, Paul Menzel wrote:
>
>>> Am 08.11.21 um 09:15 schrieb Shirish S:
>>>> limit the MPO rejection only for DCN1x as its not required on later
>>>
>>> it’s
>>>
>>>> versions.
>>>
>>> Where is it documented, that it’s not required for later versions?
>>
>> This is a workaround to avoid system hang & I've verified its not 
>> required DCN2.0.
>
> Please extend the commit message with that information, and also add 
> how you verified, that it’s not required for DCN2.0 exactly. (Just 
> test one system?)
>
>> We generally don't have documentation for WA's.
>
> WA is workaround?

yes.

Regards,

Shirish S

>
>
> Kind regards,
>
> Paul
>
>
>>> Shortly describing the implementation is also useful. Something 
>>> like: Require `fill_dc_scaling_info()` to receive the device to be 
>>> able to check the version.
>>>
>>>> Fixes: d89f6048bdcb ("drm/amd/display: Reject non-zero src_y and 
>>>> src_x for video planes")
>>>>
>>>
>>> I’d remove the blank line.
>>>
>>>> Signed-off-by: Shirish S <shirish.s at amd.com>
>>>> ---
>>>>   .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 20 
>>>> ++++++++++---------
>>>>   1 file changed, 11 insertions(+), 9 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c 
>>>> b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>>>> index 1e26d9be8993..26b29d561919 100644
>>>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>>>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>>>> @@ -4572,7 +4572,8 @@ static void 
>>>> get_min_max_dc_plane_scaling(struct drm_device *dev,
>>>>   }
>>>>     -static int fill_dc_scaling_info(const struct drm_plane_state 
>>>> *state,
>>>> +static int fill_dc_scaling_info(struct amdgpu_device *adev,
>>>> +                const struct drm_plane_state *state,
>>>>                   struct dc_scaling_info *scaling_info)
>>>>   {
>>>>       int scale_w, scale_h, min_downscale, max_upscale;
>>>> @@ -4586,7 +4587,8 @@ static int fill_dc_scaling_info(const struct 
>>>> drm_plane_state *state,
>>>>       /*
>>>>        * For reasons we don't (yet) fully understand a non-zero
>>>>        * src_y coordinate into an NV12 buffer can cause a
>>>> -     * system hang. To avoid hangs (and maybe be overly cautious)
>>>> +     * system hang on DCN1x.
>>>> +     * To avoid hangs (and maybe be overly cautious)
>>>
>>> I’d remove the added line break.
>>>
>>>>        * let's reject both non-zero src_x and src_y.
>>>>        *
>>>>        * We currently know of only one use-case to reproduce a
>>>> @@ -4594,10 +4596,10 @@ static int fill_dc_scaling_info(const 
>>>> struct drm_plane_state *state,
>>>>        * is to gesture the YouTube Android app into full screen
>>>>        * on ChromeOS.
>>>>        */
>>>> -    if (state->fb &&
>>>> -        state->fb->format->format == DRM_FORMAT_NV12 &&
>>>> -        (scaling_info->src_rect.x != 0 ||
>>>> -         scaling_info->src_rect.y != 0))
>>>> +    if (((adev->ip_versions[DCE_HWIP][0] == IP_VERSION(1, 0, 0)) ||
>>>> +        (adev->ip_versions[DCE_HWIP][0] == IP_VERSION(1, 0, 1))) &&
>>>> +        (state->fb && state->fb->format->format == DRM_FORMAT_NV12 &&
>>>> +        (scaling_info->src_rect.x != 0 || scaling_info->src_rect.y 
>>>> != 0)))
>>>>           return -EINVAL;
>>>>         scaling_info->src_rect.width = state->src_w >> 16;
>>>> @@ -5503,7 +5505,7 @@ static int fill_dc_plane_attributes(struct 
>>>> amdgpu_device *adev,
>>>>       int ret;
>>>>       bool force_disable_dcc = false;
>>>>   -    ret = fill_dc_scaling_info(plane_state, &scaling_info);
>>>> +    ret = fill_dc_scaling_info(adev, plane_state, &scaling_info);
>>>>       if (ret)
>>>>           return ret;
>>>>   @@ -7566,7 +7568,7 @@ static int dm_plane_atomic_check(struct 
>>>> drm_plane *plane,
>>>>       if (ret)
>>>>           return ret;
>>>>   -    ret = fill_dc_scaling_info(new_plane_state, &scaling_info);
>>>> +    ret = fill_dc_scaling_info(adev, new_plane_state, &scaling_info);
>>>>       if (ret)
>>>>           return ret;
>>>>   @@ -9014,7 +9016,7 @@ static void amdgpu_dm_commit_planes(struct 
>>>> drm_atomic_state *state,
>>>> bundle->surface_updates[planes_count].gamut_remap_matrix = 
>>>> &dc_plane->gamut_remap_matrix;
>>>>           }
>>>>   -        fill_dc_scaling_info(new_plane_state,
>>>> +        fill_dc_scaling_info(dm->adev, new_plane_state,
>>>> &bundle->scaling_infos[planes_count]);
>>>> bundle->surface_updates[planes_count].scaling_info =
>>>>