drm/i915/dg2: Skip output init on PHY calibration failure

If one of our PHYs fails to complete calibration, we should skip the
general initialization of the corresponding output.  Most likely this is
going to happen on outputs that don't actually exist on the board; in
theory we should have already decided to skip this output based on the
VBT, but we can't always rely on the VBT being accurate.

Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220223165421.3949883-1-matthew.d.roper@intel.com

drivers/gpu/drm/i915/display/intel_ddi.c

@@ -4308,6 +4308,14 @@ void intel_ddi_init(struct drm_i915_private *dev_priv, enum port port)
 		return;
 	}
 
+	if (intel_phy_is_snps(dev_priv, phy) &&
+	    dev_priv->snps_phy_failed_calibration & BIT(phy)) {
+		drm_dbg_kms(&dev_priv->drm,
+			    "SNPS PHY %c failed to calibrate; output will not be used.\n",
+			    phy_name(phy));
+		return;
+	}
+
 	dig_port = kzalloc(sizeof(*dig_port), GFP_KERNEL);
 	if (!dig_port)
 		return;

drivers/gpu/drm/i915/display/intel_snps_phy.c

@@ -32,10 +32,14 @@ void intel_snps_phy_wait_for_calibration(struct drm_i915_private *i915)
 		if (!intel_phy_is_snps(i915, phy))
 			continue;
 
+		/*
+		 * If calibration does not complete successfully, we'll remember
+		 * which phy was affected and skip setup of the corresponding
+		 * output later.
+		 */
 		if (intel_de_wait_for_clear(i915, DG2_PHY_MISC(phy),
 					    DG2_PHY_DP_TX_ACK_MASK, 25))
-			drm_err(&i915->drm, "SNPS PHY %c failed to calibrate after 25ms.\n",
-				phy_name(phy));
+			i915->snps_phy_failed_calibration |= BIT(phy);
 	}
 }
 

drivers/gpu/drm/i915/i915_drv.h

@@ -837,8 +837,16 @@ struct drm_i915_private {
 
 	bool irq_enabled;
 
-	/* perform PHY state sanity checks? */
-	bool chv_phy_assert[2];
+	union {
+		/* perform PHY state sanity checks? */
+		bool chv_phy_assert[2];
+
+		/*
+		 * DG2: Mask of PHYs that were not calibrated by the firmware
+		 * and should not be used.
+		 */
+		u8 snps_phy_failed_calibration;
+	};
 
 	bool ipc_enabled;