[PATCH 1/2] drm/amdgpu: don't clean the framebuffer for VF

[Ding, Pixel]

Hi Christian,

The underlying host driver clears VF’s framebuffer when guest driver shake hands with it, that is done before guest driver init. I think it’s unnecessary to clear FB again even with GPU for VF.

— 
Sincerely Yours,
Pixel





On 06/02/2017, 4:49 PM, "Koenig, Christian" <Christian.Koenig at amd.com> wrote:

>Am 06.02.2017 um 07:24 schrieb Pixel Ding:
>> The SRIOV host driver cleans framebuffer for each VF, guest driver
>> needn't this action which costs much time on some virtualization
>> platform, otherwise it might get timeout to initialize.
>>
>> Signed-off-by: Pixel Ding <Pixel.Ding at amd.com>
>> ---
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_fb.c | 4 +++-
>>   1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fb.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_fb.c
>> index 1e735c4..f1eb4f5 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fb.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fb.c
>> @@ -242,7 +242,9 @@ static int amdgpufb_create(struct drm_fb_helper *helper,
>>   	/* setup helper */
>>   	rfbdev->helper.fb = fb;
>>   
>> -	memset_io(abo->kptr, 0x0, amdgpu_bo_size(abo));
>> +	if (!amdgpu_sriov_vf(adev)) {
>> +		memset_io(abo->kptr, 0x0, amdgpu_bo_size(abo));
>> +	}
>
>Nit pick only, but coding style says to not use "{" "}" in an if without 
>else and only a single line of code.
>
>Additional to that I'm not sure if that's a good idea. The memory 
>allocated here might be already be used and so we need to clear it no 
>matter where it came from.
>
>It's probably easier to just set the AMDGPU_GEM_CREATE_VRAM_CLEARED in 
>the call to amdgpu_gem_object_create(). This makes the GPU clear the 
>memory before the first CPU access to it.
>
>Regards,
>Christian.
>
>>   
>>   	strcpy(info->fix.id, "amdgpudrmfb");
>>   
>
>