Re: [Intel-gfx] [PATCH v2 3/9] drm/i915: Disable all planes before modesetting any pipes

["Souza, Jose" <jose.souza@intel.com>]

On Fri, 2021-10-22 at 13:32 +0300, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> 
> Let's disable planes on all pipes affected by the modeset before
> we start doing the actual modeset. This means we have less
> random planes enabled during the modeset, and it also mirrors
> what we already do when enabling pipes on skl+ since we enable
> planes on all pipes as the very last step. As a bonus we also
> nuke a bunch og bigjoiner special casing.
> 
> I've occasionally pondered about going even furher here and
> doing the pre_plane_update() stuff for all pipes first, then
> actually disabling the planes, and finally running the rest
> of the modeset sequence. This would potentially allow
> parallelizing all the extra vblank waits across multiple pipes,
> and would make the plane disable even more atomic. But let's
> go one step a time here.
> 

Reviewed-by: José Roberto de Souza <jose.souza@intel.com>

> Cc: José Roberto de Souza <jose.souza@intel.com>
> Reviewed-by: Manasi Navare <manasi.d.navare@intel.com>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_display.c | 28 +++++++++-----------
>  1 file changed, 13 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index 3d2a1cba78c1..1d920ba83521 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -8251,18 +8251,13 @@ static void intel_old_crtc_state_disables(struct intel_atomic_state *state,
>  
>  	drm_WARN_ON(&dev_priv->drm, old_crtc_state->bigjoiner_slave);
>  
> -	intel_crtc_disable_planes(state, crtc);
> -
>  	/*
>  	 * We still need special handling for disabling bigjoiner master
>  	 * and slaves since for slave we do not have encoder or plls
>  	 * so we dont need to disable those.
>  	 */
> -	if (old_crtc_state->bigjoiner) {
> -		intel_crtc_disable_planes(state,
> -					  old_crtc_state->bigjoiner_linked_crtc);
> +	if (old_crtc_state->bigjoiner)
>  		old_crtc_state->bigjoiner_linked_crtc->active = false;
> -	}
>  
>  	/*
>  	 * We need to disable pipe CRC before disabling the pipe,
> @@ -8288,6 +8283,18 @@ static void intel_commit_modeset_disables(struct intel_atomic_state *state)
>  	u32 handled = 0;
>  	int i;
>  
> +	for_each_oldnew_intel_crtc_in_state(state, crtc, old_crtc_state,
> +					    new_crtc_state, i) {
> +		if (!intel_crtc_needs_modeset(new_crtc_state))
> +			continue;
> +
> +		if (!old_crtc_state->hw.active)
> +			continue;
> +
> +		intel_pre_plane_update(state, crtc);
> +		intel_crtc_disable_planes(state, crtc);
> +	}
> +
>  	/* Only disable port sync and MST slaves */
>  	for_each_oldnew_intel_crtc_in_state(state, crtc, old_crtc_state,
>  					    new_crtc_state, i) {
> @@ -8306,7 +8313,6 @@ static void intel_commit_modeset_disables(struct intel_atomic_state *state)
>  		    !intel_dp_mst_is_slave_trans(old_crtc_state))
>  			continue;
>  
> -		intel_pre_plane_update(state, crtc);
>  		intel_old_crtc_state_disables(state, old_crtc_state,
>  					      new_crtc_state, crtc);
>  		handled |= BIT(crtc->pipe);
> @@ -8320,14 +8326,6 @@ static void intel_commit_modeset_disables(struct intel_atomic_state *state)
>  		    old_crtc_state->bigjoiner_slave)
>  			continue;
>  
> -		intel_pre_plane_update(state, crtc);
> -		if (old_crtc_state->bigjoiner) {
> -			struct intel_crtc *slave =
> -				old_crtc_state->bigjoiner_linked_crtc;
> -
> -			intel_pre_plane_update(state, slave);
> -		}
> -
>  		if (old_crtc_state->hw.active)
>  			intel_old_crtc_state_disables(state, old_crtc_state,
>  						      new_crtc_state, crtc);