Re: [Intel-gfx] [PATCH v2 rebased 10/11] drm/i915/display: Check if pipe fastset is allowed by external dependencies

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Wed, Dec 11, 2019 at 10:45:25AM -0800, José Roberto de Souza wrote:
> Check if fastset is allowed by external dependencies like other pipes
> and transcoders.
> 
> Right now it only forces a fullmodeset when the MST master transcoder
> did not changed but the pipe of the master transcoder needs a
> fullmodeset so all slaves also needs to do a fullmodeset.
> But it will probably be need for port sync as well.
> 
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Cc: Lucas De Marchi <lucas.demarchi@intel.com>
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Cc: Manasi Navare <manasi.d.navare@intel.com>
> Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_display.c | 41 ++++++++++++++++++++
>  1 file changed, 41 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index 092412b10d7c..0c24d7dfa152 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -13930,11 +13930,52 @@ static int calc_watermark_data(struct intel_atomic_state *state)
>  	return 0;
>  }
>  
> +/**
> + * Check if fastset is allowed by external dependencies like other pipes and
> + * transcoders.
> + *
> + * Right now it only forces a fullmodeset when the MST master transcoder did
> + * not changed but the pipe of the master transcoder needs a fullmodeset so
> + * all slaves also needs to do a fullmodeset.
> + */
> +static bool
> +intel_crtc_check_external_dependencies_fastset(const struct intel_crtc_state *old_crtc_state,
> +					       struct intel_crtc_state *new_crtc_state)
> +{
> +	struct intel_atomic_state *state = to_intel_atomic_state(new_crtc_state->uapi.state);
> +	struct drm_i915_private *dev_priv = to_i915(new_crtc_state->uapi.crtc->dev);
> +	struct intel_crtc_state *new_crtc_state_iter;
> +	struct intel_crtc *crtc_iter;
> +	int i;
> +
> +	if (INTEL_GEN(dev_priv) < 12)
> +		return true;
> +
> +	if (!intel_crtc_has_type(old_crtc_state, INTEL_OUTPUT_DP_MST) ||
> +	    intel_dp_mst_is_master_trans(new_crtc_state))
> +		return true;
> +
> +	for_each_new_intel_crtc_in_state(state, crtc_iter, new_crtc_state_iter, i) {
> +		if (new_crtc_state_iter->cpu_transcoder !=
> +		    new_crtc_state->mst_master_transcoder)
> +			continue;
> +
> +		return !needs_modeset(new_crtc_state_iter);
> +	}
> +
> +	DRM_ERROR("Master MST transcoder of pipe not found\n");
> +	return false;
> +}
> +
>  static void intel_crtc_check_fastset(const struct intel_crtc_state *old_crtc_state,
>  				     struct intel_crtc_state *new_crtc_state)
>  {
>  	if (!intel_pipe_config_compare(old_crtc_state, new_crtc_state, true))
>  		return;
> +	if (!intel_crtc_check_external_dependencies_fastset(old_crtc_state,
> +							    new_crtc_state))
> +		return;

I don't think this will work. We've not yet .compute_config()'d
everything so the master assignments are still up in the air.

I think we need the logic higher up in intel_atomic_check():

for_each_crtc()
	compute_config()
	if (can_fastset())
		needs_modeset=false
		update_pipe=true;
	}
}

for_each_crtc()
	if (mst_slave && master.needs_modeset() {
		needs_modeset=true;
		update_pipe=false;
	}

for_each_crtc()
	if (update_pipe)
		copy_over_old_state();

	
+ we should probably rename/split update_pipes or add some
lkind of needs_fastset() wrapper to make this less confusing.


> +
>  
>  	new_crtc_state->uapi.mode_changed = false;
>  	new_crtc_state->update_pipe = true;
> -- 
> 2.24.1

-- 
Ville Syrjälä
Intel
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