[PATCH 1/4] drm/amdgpu/ci: disable mclk switching for high refresh rates (v2)

[Christian König]

Am 23.05.2017 um 23:26 schrieb Alex Deucher:
> Even if the vblank period would allow it, it still seems to
> be problematic on some cards.
>
> v2: fix logic inversion (Nils)
>
> bug: https://bugs.freedesktop.org/show_bug.cgi?id=96868
>
> Signed-off-by: Alex Deucher <alexander.deucher at amd.com>

Acked-by: Christian König <christian.koenig at amd.com> for the whole series.

> ---
>   drivers/gpu/drm/amd/amdgpu/ci_dpm.c | 6 ++++++
>   1 file changed, 6 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/ci_dpm.c b/drivers/gpu/drm/amd/amdgpu/ci_dpm.c
> index 6dc1410..ec93714 100644
> --- a/drivers/gpu/drm/amd/amdgpu/ci_dpm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/ci_dpm.c
> @@ -906,6 +906,12 @@ static bool ci_dpm_vblank_too_short(struct amdgpu_device *adev)
>   	u32 vblank_time = amdgpu_dpm_get_vblank_time(adev);
>   	u32 switch_limit = adev->mc.vram_type == AMDGPU_VRAM_TYPE_GDDR5 ? 450 : 300;
>   
> +	/* disable mclk switching if the refresh is >120Hz, even if the
> +	 * blanking period would allow it
> +	 */
> +	if (amdgpu_dpm_get_vrefresh(adev) > 120)
> +		return true;
> +
>   	if (vblank_time < switch_limit)
>   		return true;
>   	else