[Intel-gfx] [PATCH 1/2] drm/i915/ddi: Get AUX power domain for DP main link too

[Imre Deak]

On Thu, Jun 21, 2018 at 08:37:15PM +0300, Ville Syrjälä wrote:
> On Thu, Jun 21, 2018 at 06:58:29PM +0300, Imre Deak wrote:
> > So far we got an AUX power domain reference only for the duration of DP
> > AUX transfers. However, the followings suggest that we also need these
> > for main link functionality:
> > - The specification doesn't state whether it's needed or not for main
> >   link functionality, but suggests that these power wells need to be
> >   enabled already during display core initialization (Sequences to
> >   Initialize Display).
> > - For PSR we need to keep the AUX power well enabled.
> > - On ICL combo PHY ports (non-TC) the AUX power well is needed for
> >   link training too: while the port is enabled with a DP link training
> >   test pattern trying to toggle the AUX power well will time out.
> > - On ICL MG PHY ports (TC) the AUX power well is needed also for main
> >   link functionality (both in DP and HDMI modes).
> > - Windows enables these power wells both for main and AUX lane
> >   functionality.
> > 
> > Based on the above take an AUX power reference for main link
> > functionality too. This makes a difference only on GEN10+ (GLK+)
> > platforms, where we have separate port specific AUX power wells.
> > 
> > Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
> > Cc: Paulo Zanoni <paulo.r.zanoni at intel.com>
> > Signed-off-by: Imre Deak <imre.deak at intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_ddi.c     | 33 +++++++++++++++++++++++++++++----
> >  drivers/gpu/drm/i915/intel_display.c | 12 +++++++++++-
> >  drivers/gpu/drm/i915/intel_drv.h     |  3 ++-
> >  3 files changed, 42 insertions(+), 6 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> > index 044fe1fb9872..b09cb6969bbb 100644
> > --- a/drivers/gpu/drm/i915/intel_ddi.c
> > +++ b/drivers/gpu/drm/i915/intel_ddi.c
> > @@ -1983,15 +1983,36 @@ bool intel_ddi_get_hw_state(struct intel_encoder *encoder,
> >  	return ret;
> >  }
> >  
> > -static u64 intel_ddi_get_power_domains(struct intel_encoder *encoder)
> > +static u64 intel_ddi_get_power_domains(struct intel_encoder *encoder,
> > +				       struct intel_crtc_state *crtc_state)
> >  {
> >  	struct intel_digital_port *dig_port = enc_to_dig_port(&encoder->base);
> >  	enum pipe pipe;
> > +	u64 domains;
> >  
> > -	if (intel_ddi_get_hw_state(encoder, &pipe))
> > -		return BIT_ULL(dig_port->ddi_io_power_domain);
> > +	if (!intel_ddi_get_hw_state(encoder, &pipe))
> > +		return 0;
> >  
> > -	return 0;
> > +	domains = BIT_ULL(dig_port->ddi_io_power_domain);
> > +	if (!crtc_state)
> > +		return domains;
> > +
> > +	/*
> > +	 * TODO: Add support for MST encoders. Atm, the following should never
> > +	 * happen since this function will be called only for the primary
> > +	 * encoder which doesn't have its own pipe/crtc_state.
> > +	 */
> > +	if (WARN_ON(intel_crtc_has_type(crtc_state, INTEL_OUTPUT_DP_MST)))
> > +		return domains;
> > +
> > +	/* AUX power is only needed for (e)DP mode, not for HDMI. */
> > +	if (!intel_crtc_has_type(crtc_state, INTEL_OUTPUT_HDMI)) {
> > +		struct intel_dp *intel_dp = &dig_port->dp;
> > +
> > +		domains |= BIT_ULL(intel_dp->aux_power_domain);
> > +	}
> > +
> > +	return domains;
> >  }
> >  
> >  void intel_ddi_enable_pipe_clock(const struct intel_crtc_state *crtc_state)
> > @@ -2631,6 +2652,8 @@ static void intel_ddi_pre_enable_dp(struct intel_encoder *encoder,
> >  
> >  	WARN_ON(is_mst && (port == PORT_A || port == PORT_E));
> >  
> > +	intel_display_power_get(dev_priv, intel_dp->aux_power_domain);
> > +
> >  	intel_dp_set_link_params(intel_dp, crtc_state->port_clock,
> >  				 crtc_state->lane_count, is_mst);
> >  
> > @@ -2775,6 +2798,8 @@ static void intel_ddi_post_disable_dp(struct intel_encoder *encoder,
> >  	intel_display_power_put(dev_priv, dig_port->ddi_io_power_domain);
> >  
> >  	intel_ddi_clk_disable(encoder);
> > +
> > +	intel_display_power_put(dev_priv, intel_dp->aux_power_domain);
> >  }
> >  
> >  static void intel_ddi_post_disable_hdmi(struct intel_encoder *encoder,
> > diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> > index 2c8fef3ede54..d9fefcec4b1a 100644
> > --- a/drivers/gpu/drm/i915/intel_display.c
> > +++ b/drivers/gpu/drm/i915/intel_display.c
> > @@ -15676,11 +15676,21 @@ get_encoder_power_domains(struct drm_i915_private *dev_priv)
> >  	for_each_intel_encoder(&dev_priv->drm, encoder) {
> >  		u64 get_domains;
> >  		enum intel_display_power_domain domain;
> > +		struct intel_crtc_state *crtc_state;
> >  
> >  		if (!encoder->get_power_domains)
> >  			continue;
> >  
> > -		get_domains = encoder->get_power_domains(encoder);
> > +		/*
> > +		 * In case of a dangling encoder without a crtc we still need
> > +		 * to get power domain refs. Such encoders will be disabled
> > +		 * dropping these references.
> > +		 */
> > +		crtc_state = encoder->base.crtc ?
> > +			     to_intel_crtc_state(encoder->base.crtc->state) :
> > +			     NULL;
> 
> Actually I think we can just drop this NULL crtc state case. If the
> encoder is active it will have a crtc assigned, and only then do we
> actually shut it down if the connector/crtc is not active. So if we we
> ever did get into a situation where we didn't have the crtc we'd
> leak the power references. Also we need the crtc state to shut down
> the encoder.

Err, thanks for catching that. Confused myself reading
intel_sanitize_encoder(), thinking that we'll disable there encoders
without a crtc, but that's not the case as you pointed out. Since
encoder->base.crtc can be NULL for MST I will still keep the above and
rely on intel_ddi_get_hw_state() to skip taking power refs for that
case. Will update the comment accrodingly.

> The entire sanitize_encoder() thing is a bit wonky. In case we have an
> active encoder without a connector it won't actually do anything. I
> suppose that could at least happen with sdvo. With ddi it would required
> the port to be enabled with the wrong mode which I suppose is a
> slightly less realistic option.
> 
> Another case when we wouldn't do anything is if the port is enabled
> without any transcoder having selected it. That could happen with
> CPT/PPT DP or DDI. Other port types have the pipe select bits on the
> port so it's not possible to get into that situation.
> 
> Since we don't seem to have any mysterious bug reports about ports being
> wonky maybe these things just don't happen in practice. Or everything
> just happens to work out by accient even if don't shut things down
> cleanly.
> 
> > +
> > +		get_domains = encoder->get_power_domains(encoder, crtc_state);
> >  		for_each_power_domain(domain, get_domains)
> >  			intel_display_power_get(dev_priv, domain);
> >  	}
> > diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> > index 0c3ac0eafde0..7174429d930a 100644
> > --- a/drivers/gpu/drm/i915/intel_drv.h
> > +++ b/drivers/gpu/drm/i915/intel_drv.h
> > @@ -254,7 +254,8 @@ struct intel_encoder {
> >  			   struct intel_crtc_state *pipe_config);
> >  	/* Returns a mask of power domains that need to be referenced as part
> >  	 * of the hardware state readout code. */
> > -	u64 (*get_power_domains)(struct intel_encoder *encoder);
> > +	u64 (*get_power_domains)(struct intel_encoder *encoder,
> > +				 struct intel_crtc_state *crtc_state);
> >  	/*
> >  	 * Called during system suspend after all pending requests for the
> >  	 * encoder are flushed (for example for DP AUX transactions) and
> > -- 
> > 2.13.2
> 
> -- 
> Ville Syrjälä
> Intel