[PATCH 4/4] amd/display: indicate support for atomic async page-flips on DCN

[Alex Deucher]

On Wed, Aug 24, 2022 at 11:09 AM Simon Ser <contact at emersion.fr> wrote:
>
> amdgpu_dm_commit_planes already sets the flip_immediate flag for
> async page-flips. This flag is used to set the UNP_FLIP_CONTROL
> register. Thus, no additional change is required to handle async
> page-flips with the atomic uAPI.
>
> Note, async page-flips are still unsupported on DCE with the atomic
> uAPI. The mode_set_base callbacks unconditionally set the
> GRPH_SURFACE_UPDATE_H_RETRACE_EN field of the GRPH_FLIP_CONTROL
> register to 0, which disables async page-flips.

Can you elaborate a bit on this? We don't use hsync flips at all, even
in non-atomic, as far as I recall.  The hardware can also do immediate
flips which take effect as soon as you update the base address
register which is what we use for async updates today IIRC.

Alex

>
> Signed-off-by: Simon Ser <contact at emersion.fr>
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> Cc: Joshua Ashton <joshua at froggi.es>
> Cc: Melissa Wen <mwen at igalia.com>
> Cc: Alex Deucher <alexander.deucher at amd.com>
> Cc: Harry Wentland <hwentlan at amd.com>
> Cc: Nicholas Kazlauskas <nicholas.kazlauskas at amd.com>
> ---
>  drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 1 -
>  1 file changed, 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> index ef816bf295eb..9ab01c58bedb 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -3804,7 +3804,6 @@ static int amdgpu_dm_mode_config_init(struct amdgpu_device *adev)
>         adev_to_drm(adev)->mode_config.prefer_shadow = 0;
>         /* indicates support for immediate flip */
>         adev_to_drm(adev)->mode_config.async_page_flip = true;
> -       adev_to_drm(adev)->mode_config.atomic_async_page_flip_not_supported = true;
>
>         adev_to_drm(adev)->mode_config.fb_base = adev->gmc.aper_base;
>
> --
> 2.37.2
>
>