[PATCH] drm/msm/mdp4: flush vblank event on disable

[Abhinav Kumar]

On 11/27/2023 1:54 PM, Dmitry Baryshkov wrote:
> Flush queued events when disabling the crtc. This avoids timeouts when
> we come back and wait for dependencies (like the previous frame's
> flip_done).
> 
> Fixes: c8afe684c95c ("drm/msm: basic KMS driver for snapdragon")
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
> ---
>   drivers/gpu/drm/msm/disp/mdp4/mdp4_crtc.c | 9 +++++++++
>   1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/gpu/drm/msm/disp/mdp4/mdp4_crtc.c b/drivers/gpu/drm/msm/disp/mdp4/mdp4_crtc.c
> index 169f9de4a12a..3100957225a7 100644
> --- a/drivers/gpu/drm/msm/disp/mdp4/mdp4_crtc.c
> +++ b/drivers/gpu/drm/msm/disp/mdp4/mdp4_crtc.c
> @@ -269,6 +269,7 @@ static void mdp4_crtc_atomic_disable(struct drm_crtc *crtc,
>   {
>   	struct mdp4_crtc *mdp4_crtc = to_mdp4_crtc(crtc);
>   	struct mdp4_kms *mdp4_kms = get_kms(crtc);
> +	unsigned long flags;
>   
>   	DBG("%s", mdp4_crtc->name);
>   
> @@ -281,6 +282,14 @@ static void mdp4_crtc_atomic_disable(struct drm_crtc *crtc,
>   	mdp_irq_unregister(&mdp4_kms->base, &mdp4_crtc->err);
>   	mdp4_disable(mdp4_kms);
>   
> +	if (crtc->state->event && !crtc->state->active) {
> +		WARN_ON(mdp4_crtc->event);

Do you need a WARN_ON() here? Just wondering how often this might happen 
and spam.

otherwise LGTM.

> +		spin_lock_irqsave(&mdp4_kms->dev->event_lock, flags);
> +		drm_crtc_send_vblank_event(crtc, crtc->state->event);
> +		crtc->state->event = NULL;
> +		spin_unlock_irqrestore(&mdp4_kms->dev->event_lock, flags);
> +	}
> +
>   	mdp4_crtc->enabled = false;
>   }
>