[v2,11/23] drm/i915: Handle the TCCOLD power-down event

Submitted by Imre Deak on June 20, 2019, 2:05 p.m.

Details

Message ID 20190620140600.11357-12-imre.deak@intel.com
State New
Headers show
Series "drm/i915: Fix TypeC port mode switching" ( rev: 7 6 5 4 3 ) in Intel GFX

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Commit Message

Imre Deak June 20, 2019, 2:05 p.m.
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)

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 | 23 +++++++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)

Patch hide | download patch | download mbox

diff --git a/drivers/gpu/drm/i915/display/intel_tc.c b/drivers/gpu/drm/i915/display/intel_tc.c
index a02513814392..fffe4c4a6602 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 == -1);
+
 	return (lane_mask & DP_LANE_ASSIGNMENT_MASK(tc_port)) >>
 	       DP_LANE_ASSIGNMENT_SHIFT(tc_port);
 }
@@ -89,6 +91,12 @@  static u32 tc_port_live_status_mask(struct intel_digital_port *dig_port)
 
 	val = I915_READ(PORT_TX_DFLEXDPSP);
 
+	if (val == -1) {
+		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))
@@ -113,7 +121,7 @@  static bool icl_tc_phy_status_complete(struct intel_digital_port *dig_port)
 	       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);
@@ -122,6 +130,14 @@  static void icl_tc_phy_set_safe_mode(struct intel_digital_port *dig_port,
 
 	val = I915_READ(PORT_TX_DFLEXDPCSSS);
 
+	if (val == -1) {
+		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)
 		val |= DP_PHY_MODE_STATUS_NOT_SAFE(tc_port);
@@ -131,6 +147,8 @@  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;
 }
 
 /*
@@ -169,7 +187,8 @@  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;

Comments

On Thu, Jun 20, 2019 at 05:05:48PM +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)

We don't seem to care about the all 1s in icl_tc_phy_status_complete()
and icl_tc_phy_is_in_safe_mode(). Is that OK?

> 
> 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 | 23 +++++++++++++++++++++--
>  1 file changed, 21 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_tc.c b/drivers/gpu/drm/i915/display/intel_tc.c
> index a02513814392..fffe4c4a6602 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 == -1);
> +
>  	return (lane_mask & DP_LANE_ASSIGNMENT_MASK(tc_port)) >>
>  	       DP_LANE_ASSIGNMENT_SHIFT(tc_port);
>  }
> @@ -89,6 +91,12 @@ static u32 tc_port_live_status_mask(struct intel_digital_port *dig_port)
>  
>  	val = I915_READ(PORT_TX_DFLEXDPSP);
>  
> +	if (val == -1) {

Not sure I like this -1 use. I don't think we typically use it elsewhere
in similar context.

> +		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))
> @@ -113,7 +121,7 @@ static bool icl_tc_phy_status_complete(struct intel_digital_port *dig_port)
>  	       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);
> @@ -122,6 +130,14 @@ static void icl_tc_phy_set_safe_mode(struct intel_digital_port *dig_port,
>  
>  	val = I915_READ(PORT_TX_DFLEXDPCSSS);
>  
> +	if (val == -1) {
> +		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)
>  		val |= DP_PHY_MODE_STATUS_NOT_SAFE(tc_port);
> @@ -131,6 +147,8 @@ 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;
>  }
>  
>  /*
> @@ -169,7 +187,8 @@ 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;
> -- 
> 2.17.1
On Tue, Jun 25, 2019 at 04:17:35PM +0300, Ville Syrjälä wrote:
> On Thu, Jun 20, 2019 at 05:05:48PM +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)
> 
> We don't seem to care about the all 1s in icl_tc_phy_status_complete()
> and icl_tc_phy_is_in_safe_mode(). Is that OK?

Err, probably not ok, thanks for spotting it.

The cirumstances when and why "TCCOLD" would be entered is badly
specified and imo a bad HW interface (the driver doesn't seem to have
any control of it, the state will be just entered).

My best guess is that only the DP-alt mode specific parts power down in
the TCCOLD state and when that happens the TBT-alt mode is still
operational.

Based on the above assumption (and that safe-mode=TBT-alt
unsafe-mode=DP-alt/legacy), I can change icl_tc_phy_state_complete() to
return false and icl_tc_phy_is_in_safe_mode() to return true if they
detect the TCCOLD state, also adding a debug log about these events.

> 
> > 
> > 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 | 23 +++++++++++++++++++++--
> >  1 file changed, 21 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/display/intel_tc.c b/drivers/gpu/drm/i915/display/intel_tc.c
> > index a02513814392..fffe4c4a6602 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 == -1);
> > +
> >  	return (lane_mask & DP_LANE_ASSIGNMENT_MASK(tc_port)) >>
> >  	       DP_LANE_ASSIGNMENT_SHIFT(tc_port);
> >  }
> > @@ -89,6 +91,12 @@ static u32 tc_port_live_status_mask(struct intel_digital_port *dig_port)
> >  
> >  	val = I915_READ(PORT_TX_DFLEXDPSP);
> >  
> > +	if (val == -1) {
> 
> Not sure I like this -1 use. I don't think we typically use it elsewhere
> in similar context.

Heh, was also voted down by José. I will use then (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))
> > @@ -113,7 +121,7 @@ static bool icl_tc_phy_status_complete(struct intel_digital_port *dig_port)
> >  	       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);
> > @@ -122,6 +130,14 @@ static void icl_tc_phy_set_safe_mode(struct intel_digital_port *dig_port,
> >  
> >  	val = I915_READ(PORT_TX_DFLEXDPCSSS);
> >  
> > +	if (val == -1) {
> > +		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)
> >  		val |= DP_PHY_MODE_STATUS_NOT_SAFE(tc_port);
> > @@ -131,6 +147,8 @@ 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;
> >  }
> >  
> >  /*
> > @@ -169,7 +187,8 @@ 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;
> > -- 
> > 2.17.1
> 
> -- 
> Ville Syrjälä
> Intel