[PATCH] drm/amdgpu: For virtual_display feature, the vblank_get_counter hook is always return 0 when there's no hardware frame counter which can be used.

[michel@xxxxxxxxxxx (Michel Dänzer)]

On 16/08/16 07:15 PM, Emily Deng wrote:
> Signed-off-by: Emily Deng <Emily.Deng at amd.com>

Please change the shortlog to be no longer than ~72 characters. Maybe
something like this for the commit log:

drm/amdgpu: Hardcode virtual DCE vblank / scanout position return values

By hardcoding 0 for the vblank counter and -EINVAL for the scanout
position return value, we signal to the core DRM code that there are no
hardware counters we can use for these.


> diff --git a/drivers/gpu/drm/amd/amdgpu/dce_virtual.c b/drivers/gpu/drm/amd/amdgpu/dce_virtual.c
> index 2ce5f90..85f14a6 100644
> --- a/drivers/gpu/drm/amd/amdgpu/dce_virtual.c
> +++ b/drivers/gpu/drm/amd/amdgpu/dce_virtual.c
> @@ -55,10 +55,7 @@ static void dce_virtual_vblank_wait(struct amdgpu_device *adev, int crtc)
>  
>  static u32 dce_virtual_vblank_get_counter(struct amdgpu_device *adev, int crtc)
>  {
> -	if (crtc >= adev->mode_info.num_crtc)
> -		return 0;
> -	else
> -		return adev->ddev->vblank[crtc].count;
> +	return 0;
>  }
>  
>  static void dce_virtual_page_flip(struct amdgpu_device *adev,
> @@ -70,13 +67,10 @@ static void dce_virtual_page_flip(struct amdgpu_device *adev,
>  static int dce_virtual_crtc_get_scanoutpos(struct amdgpu_device *adev, int crtc,
>  					u32 *vbl, u32 *position)
>  {
> -	if ((crtc < 0) || (crtc >= adev->mode_info.num_crtc))
> -		return -EINVAL;
> -
>  	*vbl = 0;
>  	*position = 0;
>  
> -	return 0;
> +	return -EINVAL;
>  }

Would it be possible to add short-circuits for the virtual display case
in amdgpu_get_crtc_scanoutpos and amdgpu_get_vblank_counter_kms, so they
don't do any unnecessary work, and remove dce_virtual_vblank_get_counter
and dce_virtual_crtc_get_scanoutpos?


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