[PATCH 3/3] drm/amd/display: Move disable interrupt into commit tail

[Kazlauskas, Nicholas]

On 2020-09-09 10:28 a.m., Aurabindo Pillai wrote:
> [Why&How]
> Since there is no need for accessing crtc state in the interrupt
> handler, interrupts need not be disabled well in advance, and
> can be moved to commit_tail where it should be.
> 
> Signed-off-by: Aurabindo Pillai <aurabindo.pillai at amd.com>

This patch is fine in idea, but it'll need the reference counting fixed 
in patch #2 first and be adjusted after.

Regards,
Nicholas Kazlauskas

> ---
>   .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 38 +++++--------------
>   1 file changed, 10 insertions(+), 28 deletions(-)
> 
> 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 0603436a3313..a40de242e04a 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -7488,34 +7488,6 @@ static int amdgpu_dm_atomic_commit(struct drm_device *dev,
>   				   struct drm_atomic_state *state,
>   				   bool nonblock)
>   {
> -	struct drm_crtc *crtc;
> -	struct drm_crtc_state *old_crtc_state, *new_crtc_state;
> -	struct amdgpu_device *adev = drm_to_adev(dev);
> -	int i;
> -
> -	/*
> -	 * We evade vblank and pflip interrupts on CRTCs that are undergoing
> -	 * a modeset, being disabled, or have no active planes.
> -	 *
> -	 * It's done in atomic commit rather than commit tail for now since
> -	 * some of these interrupt handlers access the current CRTC state and
> -	 * potentially the stream pointer itself.
> -	 *
> -	 * Since the atomic state is swapped within atomic commit and not within
> -	 * commit tail this would leave to new state (that hasn't been committed yet)
> -	 * being accesssed from within the handlers.
> -	 *
> -	 * TODO: Fix this so we can do this in commit tail and not have to block
> -	 * in atomic check.
> -	 */
> -	for_each_oldnew_crtc_in_state(state, crtc, old_crtc_state, new_crtc_state, i) {
> -		struct amdgpu_crtc *acrtc = to_amdgpu_crtc(crtc);
> -
> -		if (old_crtc_state->active &&
> -		    (!new_crtc_state->active ||
> -		     drm_atomic_crtc_needs_modeset(new_crtc_state)))
> -			manage_dm_interrupts(adev, acrtc, false);
> -	}
>   	/*
>   	 * Add check here for SoC's that support hardware cursor plane, to
>   	 * unset legacy_cursor_update
> @@ -7566,6 +7538,16 @@ static void amdgpu_dm_atomic_commit_tail(struct drm_atomic_state *state)
>   		dc_resource_state_copy_construct_current(dm->dc, dc_state);
>   	}
>   
> +	for_each_oldnew_crtc_in_state (state, crtc, old_crtc_state,
> +				       new_crtc_state, i) {
> +		acrtc = to_amdgpu_crtc(crtc);
> +
> +		if (old_crtc_state->active &&
> +		    (!new_crtc_state->active ||
> +		     drm_atomic_crtc_needs_modeset(new_crtc_state)))
> +			manage_dm_interrupts(adev, acrtc, false);
> +	}
> +
>   	/* update changed items */
>   	for_each_oldnew_crtc_in_state(state, crtc, old_crtc_state, new_crtc_state, i) {
>   		struct amdgpu_crtc *acrtc = to_amdgpu_crtc(crtc);
>