Re: [Intel-gfx] [PATCH 01/13] drm/i915/tc: Fix TypeC port init/resume time sanitization

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

On Tue, 2021-09-21 at 03:23 +0300, Imre Deak wrote:
> Atm during driver loading and system resume TypeC ports are accessed
> before their HW/SW state is synced. Move the TypeC port sanitization to
> the encoder's sync_state hook to fix this.
> 
> Fixes: f9e76a6e68d3 ("drm/i915: Add an encoder hook to sanitize its state during init/resume")
> Cc: José Roberto de Souza <jose.souza@intel.com>
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Signed-off-by: Imre Deak <imre.deak@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_ddi.c     |  8 +++++++-
>  drivers/gpu/drm/i915/display/intel_display.c | 20 +++++---------------
>  2 files changed, 12 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index bba0ab99836b1..c4ed4675f5791 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -3840,7 +3840,13 @@ void hsw_ddi_get_config(struct intel_encoder *encoder,
>  static void intel_ddi_sync_state(struct intel_encoder *encoder,
>  				 const struct intel_crtc_state *crtc_state)
>  {
> -	if (intel_crtc_has_dp_encoder(crtc_state))
> +	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
> +	enum phy phy = intel_port_to_phy(i915, encoder->port);
> +
> +	if (intel_phy_is_tc(i915, phy))
> +		intel_tc_port_sanitize(enc_to_dig_port(encoder));

Okay at this point we will not have any mst encoder, so the check is not needed.

> +
> +	if (crtc_state && intel_crtc_has_dp_encoder(crtc_state))
>  		intel_dp_sync_state(encoder, crtc_state);
>  }
>  
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index f6c0c595f6313..8547842935389 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -12194,18 +12194,16 @@ static void intel_modeset_readout_hw_state(struct drm_device *dev)
>  	readout_plane_state(dev_priv);
>  
>  	for_each_intel_encoder(dev, encoder) {
> +		struct intel_crtc_state *crtc_state = NULL;
> +
>  		pipe = 0;
>  
>  		if (encoder->get_hw_state(encoder, &pipe)) {
> -			struct intel_crtc_state *crtc_state;
> -
>  			crtc = intel_get_crtc_for_pipe(dev_priv, pipe);
>  			crtc_state = to_intel_crtc_state(crtc->base.state);
>  
>  			encoder->base.crtc = &crtc->base;
>  			intel_encoder_get_config(encoder, crtc_state);
> -			if (encoder->sync_state)
> -				encoder->sync_state(encoder, crtc_state);
>  
>  			/* read out to slave crtc as well for bigjoiner */
>  			if (crtc_state->bigjoiner) {
> @@ -12220,6 +12218,9 @@ static void intel_modeset_readout_hw_state(struct drm_device *dev)
>  			encoder->base.crtc = NULL;
>  		}
>  
> +		if (encoder->sync_state)
> +			encoder->sync_state(encoder, crtc_state);

Call sync_state() with a null crtc_state will cause a crash in gen11_dsi_sync_state().

gen11_dsi_sync_state() is the only user of crtc_state but it only wants to know what is the pipe, maybe to be safer change the argument to enum pipe?

> +
>  		drm_dbg_kms(&dev_priv->drm,
>  			    "[ENCODER:%d:%s] hw state readout: %s, pipe %c\n",
>  			    encoder->base.base.id, encoder->base.name,
> @@ -12502,17 +12503,6 @@ intel_modeset_setup_hw_state(struct drm_device *dev,
>  	intel_modeset_readout_hw_state(dev);
>  
>  	/* HW state is read out, now we need to sanitize this mess. */
> -
> -	/* Sanitize the TypeC port mode upfront, encoders depend on this */
> -	for_each_intel_encoder(dev, encoder) {
> -		enum phy phy = intel_port_to_phy(dev_priv, encoder->port);
> -
> -		/* We need to sanitize only the MST primary port. */
> -		if (encoder->type != INTEL_OUTPUT_DP_MST &&
> -		    intel_phy_is_tc(dev_priv, phy))
> -			intel_tc_port_sanitize(enc_to_dig_port(encoder));
> -	}
> -
>  	get_encoder_power_domains(dev_priv);
>  
>  	if (HAS_PCH_IBX(dev_priv))