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

Imre Deak
2019-06-20T14:06:24Z

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(-)

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;