[PATCH] drm/amd/display: Enable fast plane updates on DCN3.2 and above when state->allow_modeset = true

[Mario Limonciello]

On 10/7/2023 00:41, Tianci Yin wrote:
> From: tiancyin <tianci.yin at amd.com>
> 
> [why]
> When cursor moves across screen boarder, lag cursor observed,
> since subvp settings need to sync up with vblank, that cause
> cursor updates being delayed.
> 
> [how]
> Enable fast plane updates on DCN3.2 to fix it.
> 
> Signed-off-by: tiancyin <tianci.yin at amd.com>
> ---
>   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 3 ++-
>   1 file changed, 2 insertions(+), 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 c21726bdbca2..25a0bd314fe5 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -9879,6 +9879,7 @@ static bool should_reset_plane(struct drm_atomic_state *state,
>   	struct drm_plane *other;
>   	struct drm_plane_state *old_other_state, *new_other_state;
>   	struct drm_crtc_state *new_crtc_state;
> +	struct amdgpu_device *adev = drm_to_adev(plane->dev);
>   	int i;
>   
>   	/*
> @@ -9886,7 +9887,7 @@ static bool should_reset_plane(struct drm_atomic_state *state,
>   	 * enough to determine when we need to reset all the planes on
>   	 * the stream.
>   	 */
> -	if (state->allow_modeset)
> +	if (adev->ip_versions[DCE_HWIP][0] < IP_VERSION(3, 2, 0) && state->allow_modeset)
>   		return true;
>   
>   	/* Exit early if we know that we're adding or removing the plane. */

The comment associated with this says that this hack should go when 
there are sufficient checks.

If there are enough checks for DCN3.2, isn't it likely there are enough 
for earlier products too?  None of the rest of the code checks a 
specific IP version.

Maybe the whole commit/block should go?