Re: [PATCH v3 11/23] drm/i915: Handle the TCCOLD power-down event

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

On Thu, Jun 27, 2019 at 01:09:13PM +0300, Imre Deak wrote:
> On Thu, Jun 27, 2019 at 01:12:51AM +0300, Souza, Jose wrote:
> > On Wed, 2019-06-26 at 21:04 +0300, Imre Deak wrote:
> > > Based on a recent BSpec update (Index/21750) we must handle the
> > > TCCOLD
> > > event associated with the DP-alt mode. We can detect this event by
> > > reading an invalid all-1s value from FIA registers.
> > > 
> > > After detecting TCCOLD we will:
> > > - fall back to TBT-alt mode when attempting to switch to DP-alt mode
> > > - conclude that nothing is connected during live status detection
> > > - WARN when already in unsafe mode, since then TCCOLD is unexpected
> > > 
> > > v2:
> > > - Use DRM_DEBUG_KMS instead of DRM_DEBUG_DRIVER. (José)
> > > v3:
> > > - Use 0xffffffff instead of -1 as invalid FIA reg value.
> > >   (José, Ville)
> > > - Check for TCCOLD in icl_tc_phy_status_complete() too. (Ville)
> > > 
> > > Cc: José Roberto de Souza <jose.souza@intel.com>
> > > Cc: Rodrigo Vivi <rodrigo.vivi@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_tc.c | 33 ++++++++++++++++++++++-
> > > --
> > >  1 file changed, 29 insertions(+), 4 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/display/intel_tc.c
> > > b/drivers/gpu/drm/i915/display/intel_tc.c
> > > index 4243db6d25a7..96855250a5be 100644
> > > --- a/drivers/gpu/drm/i915/display/intel_tc.c
> > > +++ b/drivers/gpu/drm/i915/display/intel_tc.c
> > > @@ -29,6 +29,8 @@ u32 intel_tc_port_get_lane_mask(struct
> > > intel_digital_port *dig_port)
> > >  
> > >  	lane_mask = I915_READ(PORT_TX_DFLEXDPSP);
> > >  
> > > +	WARN_ON(lane_mask == 0xffffffff);
> > 
> > nit: Maybe define it?
> 
> Ok, makes sense, will add it (to this file only though, not under the
> reg definition).

I'm not sure a define is particularly helpful. All 1s is the
standard "I'm not here" response.

> 
> > 
> > #define FIA_TCCOLD_VALUE 0xffffffff
> > 
> > Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
> > 
> > 
> > > +
> > >  	return (lane_mask & DP_LANE_ASSIGNMENT_MASK(tc_port)) >>
> > >  	       DP_LANE_ASSIGNMENT_SHIFT(tc_port);
> > >  }
> > > @@ -92,6 +94,12 @@ static u32 tc_port_live_status_mask(struct
> > > intel_digital_port *dig_port)
> > >  
> > >  	val = I915_READ(PORT_TX_DFLEXDPSP);
> > >  
> > > +	if (val == 0xffffffff) {
> > > +		DRM_DEBUG_KMS("Port %s: PHY in TCCOLD, nothing
> > > connected\n",
> > > +			      dig_port->tc_port_name);
> > > +		return mask;
> > > +	}
> > > +
> > >  	if (val & TC_LIVE_STATE_TBT(tc_port))
> > >  		mask |= BIT(TC_PORT_TBT_ALT);
> > >  	if (val & TC_LIVE_STATE_TC(tc_port))
> > > @@ -111,12 +119,19 @@ static bool icl_tc_phy_status_complete(struct
> > > intel_digital_port *dig_port)
> > >  {
> > >  	struct drm_i915_private *dev_priv = to_i915(dig_port-
> > > >base.base.dev);
> > >  	enum tc_port tc_port = intel_port_to_tc(dev_priv, dig_port-
> > > >base.port);
> > > +	u32 val;
> > >  
> > > -	return I915_READ(PORT_TX_DFLEXDPPMS) &
> > > -	       DP_PHY_MODE_STATUS_COMPLETED(tc_port);
> > > +	val = I915_READ(PORT_TX_DFLEXDPPMS);
> > > +	if (val == 0xffffffff) {
> > > +		DRM_DEBUG_KMS("Port %s: PHY in TCCOLD, assuming not
> > > complete\n",
> > > +			      dig_port->tc_port_name);
> > > +		return false;
> > > +	}
> > > +
> > > +	return val & DP_PHY_MODE_STATUS_COMPLETED(tc_port);
> > >  }
> > >  
> > > -static void icl_tc_phy_set_safe_mode(struct intel_digital_port
> > > *dig_port,
> > > +static bool icl_tc_phy_set_safe_mode(struct intel_digital_port
> > > *dig_port,
> > >  				     bool enable)
> > >  {
> > >  	struct drm_i915_private *dev_priv = to_i915(dig_port-
> > > >base.base.dev);
> > > @@ -124,6 +139,13 @@ static void icl_tc_phy_set_safe_mode(struct
> > > intel_digital_port *dig_port,
> > >  	u32 val;
> > >  
> > >  	val = I915_READ(PORT_TX_DFLEXDPCSSS);
> > > +	if (val == 0xffffffff) {
> > > +		DRM_DEBUG_KMS("Port %s: PHY in TCCOLD, can't set safe-
> > > mode to %s\n",
> > > +			      dig_port->tc_port_name,
> > > +			      enableddisabled(enable));
> > > +
> > > +		return false;
> > > +	}
> > >  
> > >  	val &= ~DP_PHY_MODE_STATUS_NOT_SAFE(tc_port);
> > >  	if (!enable)
> > > @@ -134,6 +156,8 @@ static void icl_tc_phy_set_safe_mode(struct
> > > intel_digital_port *dig_port,
> > >  	if (enable && wait_for(!icl_tc_phy_status_complete(dig_port),
> > > 10))
> > >  		DRM_DEBUG_KMS("Port %s: PHY complete clear timed
> > > out\n",
> > >  			      dig_port->tc_port_name);
> > > +
> > > +	return true;
> > >  }
> > >  
> > >  /*
> > > @@ -172,7 +196,8 @@ static bool icl_tc_phy_connect(struct
> > > intel_digital_port *dig_port)
> > >  		return false;
> > >  	}
> > >  
> > > -	icl_tc_phy_set_safe_mode(dig_port, false);
> > > +	if (!icl_tc_phy_set_safe_mode(dig_port, false))
> > > +		return false;
> > >  
> > >  	if (dig_port->tc_mode == TC_PORT_LEGACY)
> > >  		return true;

-- 
Ville Syrjälä
Intel
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