[Intel-gfx] [PATCH v6 4/7] drm/i915: Do not call drm_crtc_arm_vblank_event in async flips

[Ville Syrjälä]

On Fri, Aug 07, 2020 at 03:05:48PM +0530, Karthik B S wrote:
> Since the flip done event will be sent in the flip_done_handler,
> no need to add the event to the list and delay it for later.
> 
> v2: -Moved the async check above vblank_get as it
>      was causing issues for PSR.
> 
> v3: -No need to wait for vblank to pass, as this wait was causing a
>      16ms delay once every few flips.
> 
> v4: -Rebased.
> 
> v5: -Rebased.
> 
> v6: -Rebased.
> 
> Signed-off-by: Karthik B S <karthik.b.s at intel.com>
> Signed-off-by: Vandita Kulkarni <vandita.kulkarni at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_sprite.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_sprite.c b/drivers/gpu/drm/i915/display/intel_sprite.c
> index c26ca029fc0a..2b2d96c59d7f 100644
> --- a/drivers/gpu/drm/i915/display/intel_sprite.c
> +++ b/drivers/gpu/drm/i915/display/intel_sprite.c
> @@ -93,6 +93,9 @@ void intel_pipe_update_start(const struct intel_crtc_state *new_crtc_state)
>  	DEFINE_WAIT(wait);
>  	u32 psr_status;
>  
> +	if (new_crtc_state->uapi.async_flip)
> +		goto irq_disable;

We shouldn't really need the irq disable at all if we don't do the
vblank evade. And if we only write ctl+surf then atomicity is already
guaranteed by the hw.

> +
>  	vblank_start = adjusted_mode->crtc_vblank_start;
>  	if (adjusted_mode->flags & DRM_MODE_FLAG_INTERLACE)
>  		vblank_start = DIV_ROUND_UP(vblank_start, 2);
> @@ -206,7 +209,7 @@ void intel_pipe_update_end(struct intel_crtc_state *new_crtc_state)
>  	 * Would be slightly nice to just grab the vblank count and arm the
>  	 * event outside of the critical section - the spinlock might spin for a
>  	 * while ... */
> -	if (new_crtc_state->uapi.event) {
> +	if (new_crtc_state->uapi.event && !new_crtc_state->uapi.async_flip) {
>  		drm_WARN_ON(&dev_priv->drm,
>  			    drm_crtc_vblank_get(&crtc->base) != 0);
>  
> @@ -220,6 +223,9 @@ void intel_pipe_update_end(struct intel_crtc_state *new_crtc_state)
>  
>  	local_irq_enable();
>  
> +	if (new_crtc_state->uapi.async_flip)
> +		return;
> +
>  	if (intel_vgpu_active(dev_priv))
>  		return;
>  
> -- 
> 2.22.0

-- 
Ville Syrjälä
Intel