[PATCH v3 3/3] drm/amd: enable S/G for RAVEN chip

[Michel Dänzer]

On 2019-07-24 4:41 p.m., Koenig, Christian wrote:
> Am 24.07.19 um 16:32 schrieb Grodzovsky, Andrey:
>> On 7/24/19 10:25 AM, Koenig, Christian wrote:
>>> Am 24.07.19 um 16:10 schrieb Andrey Grodzovsky:
>>>> From: Shirish S <shirish.s at amd.com>
>>>>
>>>> enables gpu_vm_support in dm and adds
>>>> AMDGPU_GEM_DOMAIN_GTT as supported domain
>>>>
>>>> v2:
>>>> Move BO placement logic into amdgpu_display_supported_domains
>>>>
>>>> v3:
>>>> Use amdgpu_bo_validate_uswc in amdgpu_display_supported_domains.
>>>>
>>>> Change-Id: If34300beaa60be2d36170b7b5b096ec644502b20
>>>> Signed-off-by: Shirish S <shirish.s at amd.com>
>>>> Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky at amd.com>
>>> Actually that doesn't look like a good idea to me.
>>>
>>> It is still perfectly possible (and wanted!) that the USWC flag was not
>>> set in the first place by userspace.
>>>
>>> Is that still checked somewhere?
>>>
>>> Regards,
>>> Christian.
>>
>> Not sure I understand here, can you elaborate ?
> 
> It's still possible that userspace doesn't set the USWC flag and there 
> actually might be good reasons for that.
> 
> Do we still have a check for this case somewhere?

It sounds like you're misunderstanding what this patch does, probably
due to the weird amdgpu_bo_validate_uswc API.
amdgpu_display_supported_domains doesn't set the flag for the BO itself.
Changing the helper API to what we suggested should clear this up.

(Maybe the new helper function should be used in
amdgpu_display_supported_domains in patch 2 already, or in yet another
separate patch?)


-- 
Earthling Michel Dänzer               |              https://www.amd.com
Libre software enthusiast             |             Mesa and X developer