Re: [PATCH] drm/i915/dp: Fix connector DSC HW state readout

[Drew Davenport <ddavenport@chromium.org>]

On Mon, Feb 05, 2024 at 03:26:31PM +0200, Imre Deak wrote:
> The DSC HW state of DP connectors is read out during driver loading and
> system resume in intel_modeset_update_connector_atomic_state(). This
> function is called for all connectors though and so the state of DSI
> connectors will also get updated incorrectly, triggering a WARN there
> wrt. the DSC decompression AUX device.
> 
> Fix the above by moving the DSC state readout to a new DP connector
> specific sync_state() hook. This is anyway the logical place to update
> the connector object's state vs. the connector's atomic state.
> 
> Fixes: b2608c6b3212 ("drm/i915/dp_mst: Enable MST DSC decompression for all streams")
> Reported-by: Drew Davenport <ddavenport@chromium.org>
> Closes: https://lore.kernel.org/all/Zb0q8IDVXS0HxJyj@chromium.org
> Signed-off-by: Imre Deak <imre.deak@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_display_types.h |  7 +++++++
>  drivers/gpu/drm/i915/display/intel_dp.c            | 13 +++++++++++++
>  drivers/gpu/drm/i915/display/intel_dp.h            |  2 ++
>  drivers/gpu/drm/i915/display/intel_dp_mst.c        |  1 +
>  drivers/gpu/drm/i915/display/intel_modeset_setup.c | 13 ++++++-------
>  5 files changed, 29 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
> index ae2e8cff9d691..6e1ddd05bd504 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -609,6 +609,13 @@ struct intel_connector {
>  	 * and active (i.e. dpms ON state). */
>  	bool (*get_hw_state)(struct intel_connector *);
>  
> +	/*
> +	 * Optional hook called during init/resume to sync any state
> +	 * stored in the connector (eg. DSC state) wrt. the HW state.
> +	 */
> +	void (*sync_state)(struct intel_connector *connector,
> +			   const struct intel_crtc_state *crtc_state);
> +
>  	/* Panel info for eDP and LVDS */
>  	struct intel_panel panel;
>  
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index ab415f41924d7..f8b1aab7745fd 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -5868,6 +5868,19 @@ intel_dp_connector_unregister(struct drm_connector *connector)
>  	intel_connector_unregister(connector);
>  }
>  
> +void intel_dp_connector_sync_state(struct intel_connector *connector,
> +				   const struct intel_crtc_state *crtc_state)
> +{
> +	struct drm_i915_private *i915 = to_i915(connector->base.dev);
> +
> +	if (crtc_state && crtc_state->dsc.compression_enable) {
> +		drm_WARN_ON(&i915->drm, !connector->dp.dsc_decompression_aux);
> +		connector->dp.dsc_decompression_enabled = true;
> +	} else {
> +		connector->dp.dsc_decompression_enabled = false;
> +	}
> +}
> +
>  void intel_dp_encoder_flush_work(struct drm_encoder *encoder)
>  {
>  	struct intel_digital_port *dig_port = enc_to_dig_port(to_intel_encoder(encoder));
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.h b/drivers/gpu/drm/i915/display/intel_dp.h
> index 530cc97bc42f4..f911dfab5fba9 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.h
> +++ b/drivers/gpu/drm/i915/display/intel_dp.h
> @@ -45,6 +45,8 @@ bool intel_dp_limited_color_range(const struct intel_crtc_state *crtc_state,
>  int intel_dp_min_bpp(enum intel_output_format output_format);
>  bool intel_dp_init_connector(struct intel_digital_port *dig_port,
>  			     struct intel_connector *intel_connector);
> +void intel_dp_connector_sync_state(struct intel_connector *connector,
> +				   const struct intel_crtc_state *crtc_state);
>  void intel_dp_set_link_params(struct intel_dp *intel_dp,
>  			      int link_rate, int lane_count);
>  int intel_dp_get_link_train_fallback_values(struct intel_dp *intel_dp,
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> index 5fa25a5a36b55..130c6aab86b22 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> @@ -1538,6 +1538,7 @@ static struct drm_connector *intel_dp_add_mst_connector(struct drm_dp_mst_topolo
>  		return NULL;
>  
>  	intel_connector->get_hw_state = intel_dp_mst_get_hw_state;
> +	intel_connector->sync_state = intel_dp_connector_sync_state;
>  	intel_connector->mst_port = intel_dp;
>  	intel_connector->port = port;
>  	drm_dp_mst_get_port_malloc(port);
> diff --git a/drivers/gpu/drm/i915/display/intel_modeset_setup.c b/drivers/gpu/drm/i915/display/intel_modeset_setup.c
> index 94eece7f63be3..caeca3a8442c5 100644
> --- a/drivers/gpu/drm/i915/display/intel_modeset_setup.c
> +++ b/drivers/gpu/drm/i915/display/intel_modeset_setup.c
> @@ -318,12 +318,6 @@ static void intel_modeset_update_connector_atomic_state(struct drm_i915_private
>  			const struct intel_crtc_state *crtc_state =
>  				to_intel_crtc_state(crtc->base.state);
>  
> -			if (crtc_state->dsc.compression_enable) {
> -				drm_WARN_ON(&i915->drm, !connector->dp.dsc_decompression_aux);
> -				connector->dp.dsc_decompression_enabled = true;
> -			} else {
> -				connector->dp.dsc_decompression_enabled = false;
> -			}
>  			conn_state->max_bpc = (crtc_state->pipe_bpp ?: 24) / 3;
>  		}
>  	}
> @@ -775,8 +769,9 @@ static void intel_modeset_readout_hw_state(struct drm_i915_private *i915)
>  
>  	drm_connector_list_iter_begin(&i915->drm, &conn_iter);
>  	for_each_intel_connector_iter(connector, &conn_iter) {
> +		struct intel_crtc_state *crtc_state = NULL;
> +
>  		if (connector->get_hw_state(connector)) {
> -			struct intel_crtc_state *crtc_state;
>  			struct intel_crtc *crtc;
>  
>  			connector->base.dpms = DRM_MODE_DPMS_ON;
> @@ -802,6 +797,10 @@ static void intel_modeset_readout_hw_state(struct drm_i915_private *i915)
>  			connector->base.dpms = DRM_MODE_DPMS_OFF;
>  			connector->base.encoder = NULL;
>  		}
> +
> +		if (connector->sync_state)
> +			connector->sync_state(connector, crtc_state);
> +
>  		drm_dbg_kms(&i915->drm,
>  			    "[CONNECTOR:%d:%s] hw state readout: %s\n",
>  			    connector->base.base.id, connector->base.name,
> -- 
> 2.39.2
> 

Thanks. I verified this on the JSL device that I reproed the warning on.

Tested-by: Drew Davenport <ddavenport@chromium.org>