Re: [PATCH 07/11] drm/amdgpu: add UAPI to query GFX shadow sizes

[Alex Deucher <alexdeucher@gmail.com>]

On Mon, Mar 20, 2023 at 8:31 PM Marek Olšák <maraeo@gmail.com> wrote:
>
> On Mon, Mar 20, 2023 at 1:38 PM Alex Deucher <alexander.deucher@amd.com> wrote:
>>
>> Add UAPI to query the GFX shadow buffer requirements
>> for preemption on GFX11.  UMDs need to specify the shadow
>> areas for preemption.
>>
>> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
>> ---
>>  include/uapi/drm/amdgpu_drm.h | 10 ++++++++++
>>  1 file changed, 10 insertions(+)
>>
>> diff --git a/include/uapi/drm/amdgpu_drm.h b/include/uapi/drm/amdgpu_drm.h
>> index 3d9474af6566..19a806145371 100644
>> --- a/include/uapi/drm/amdgpu_drm.h
>> +++ b/include/uapi/drm/amdgpu_drm.h
>> @@ -886,6 +886,7 @@ struct drm_amdgpu_cs_chunk_cp_gfx_shadow {
>>         #define AMDGPU_INFO_VIDEO_CAPS_DECODE           0
>>         /* Subquery id: Encode */
>>         #define AMDGPU_INFO_VIDEO_CAPS_ENCODE           1
>> +#define AMDGPU_INFO_CP_GFX_SHADOW_SIZE         0x22
>
>
> Can you put this into the device structure instead? Let's minimize the number of kernel queries as much as possible.

I guess, but one nice thing about this is that we can use the query as
a way to determine if the kernel supports this functionality or not.
If not, the query returns -ENOTSUP.

Alex


>
> Thanks,
> Marek
>