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

Imre Deak
2019-06-27T10:09:17Z

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).

>
> #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;