drm/i915: DP_PIPE_ENABLED must check transcoder on CPT

Display port pipe selection on CPT is not done with a bit in the
output register, rather it is controlled by a couple of bits in the
separate transcoder register which indicate which display port output
is connected to the transcoder.

This patch replaces the simplistic macro DP_PIPE_ENABLED with the
rather more complicated function dp_pipe_enabled which checks the
output register to see if that is enabled, and then goes on to either
check the output register pipe selection bit (on non-CPT) or the
transcoder DP selection bits (on CPT).

Before this patch, any time the mode of pipe A was changed, any
display port outputs on pipe B would get disabled as
intel_disable_pch_ports would ensure that the mode setting operation
could occur on pipe A without interference from other outputs
connected to that pch port

Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Adam Jackson <ajax@redhat.com>

drivers/gpu/drm/i915/i915_reg.h

@@ -2083,9 +2083,6 @@
 #define   DP_PIPEB_SELECT		(1 << 30)
 #define   DP_PIPE_MASK			(1 << 30)
 
-#define DP_PIPE_ENABLED(V, P) \
-	(((V) & (DP_PIPE_MASK | DP_PORT_EN)) == ((P) << 30 | DP_PORT_EN))
-
 /* Link training mode - select a suitable mode for each stage */
 #define   DP_LINK_TRAIN_PAT_1		(0 << 28)
 #define   DP_LINK_TRAIN_PAT_2		(1 << 28)

drivers/gpu/drm/i915/intel_display.c

@@ -979,11 +979,29 @@ static void assert_transcoder_disabled(struct drm_i915_private *dev_priv,
 	     pipe_name(pipe));
 }
 
+static bool dp_pipe_enabled(struct drm_i915_private *dev_priv, enum pipe pipe,
+			    int reg, u32 port_sel, u32 val)
+{
+	if ((val & DP_PORT_EN) == 0)
+		return false;
+
+	if (HAS_PCH_CPT(dev_priv->dev)) {
+		u32	trans_dp_ctl_reg = TRANS_DP_CTL(pipe);
+		u32	trans_dp_ctl = I915_READ(trans_dp_ctl_reg);
+		if ((trans_dp_ctl & TRANS_DP_PORT_SEL_MASK) != port_sel)
+			return false;
+	} else {
+		if ((val & DP_PIPE_MASK) != (pipe << 30))
+			return false;
+	}
+	return true;
+}
+
 static void assert_pch_dp_disabled(struct drm_i915_private *dev_priv,
-				   enum pipe pipe, int reg)
+				   enum pipe pipe, int reg, u32 port_sel)
 {
 	u32 val = I915_READ(reg);
-	WARN(DP_PIPE_ENABLED(val, pipe),
+	WARN(dp_pipe_enabled(dev_priv, pipe, reg, port_sel, val),
 	     "PCH DP (0x%08x) enabled on transcoder %c, should be disabled\n",
 	     reg, pipe_name(pipe));
 }
@@ -1003,9 +1021,9 @@ static void assert_pch_ports_disabled(struct drm_i915_private *dev_priv,
 	int reg;
 	u32 val;
 
-	assert_pch_dp_disabled(dev_priv, pipe, PCH_DP_B);
-	assert_pch_dp_disabled(dev_priv, pipe, PCH_DP_C);
-	assert_pch_dp_disabled(dev_priv, pipe, PCH_DP_D);
+	assert_pch_dp_disabled(dev_priv, pipe, PCH_DP_B, TRANS_DP_PORT_SEL_B);
+	assert_pch_dp_disabled(dev_priv, pipe, PCH_DP_C, TRANS_DP_PORT_SEL_C);
+	assert_pch_dp_disabled(dev_priv, pipe, PCH_DP_D, TRANS_DP_PORT_SEL_D);
 
 	reg = PCH_ADPA;
 	val = I915_READ(reg);
@@ -1334,19 +1352,24 @@ static void intel_disable_plane(struct drm_i915_private *dev_priv,
 }
 
 static void disable_pch_dp(struct drm_i915_private *dev_priv,
-			   enum pipe pipe, int reg)
+			   enum pipe pipe, int reg, u32 port_sel)
 {
 	u32 val = I915_READ(reg);
-	if (DP_PIPE_ENABLED(val, pipe))
+	if (dp_pipe_enabled(dev_priv, pipe, reg, port_sel, val)) {
+		DRM_DEBUG_KMS("Disabling pch dp %x on pipe %d\n", reg, pipe);
 		I915_WRITE(reg, val & ~DP_PORT_EN);
+	}
 }
 
 static void disable_pch_hdmi(struct drm_i915_private *dev_priv,
 			     enum pipe pipe, int reg)
 {
 	u32 val = I915_READ(reg);
-	if (HDMI_PIPE_ENABLED(val, pipe))
+	if (HDMI_PIPE_ENABLED(val, pipe)) {
+		DRM_DEBUG_KMS("Disabling pch HDMI %x on pipe %d\n",
+			      reg, pipe);
 		I915_WRITE(reg, val & ~PORT_ENABLE);
+	}
 }
 
 /* Disable any ports connected to this transcoder */
@@ -1358,9 +1381,9 @@ static void intel_disable_pch_ports(struct drm_i915_private *dev_priv,
 	val = I915_READ(PCH_PP_CONTROL);
 	I915_WRITE(PCH_PP_CONTROL, val | PANEL_UNLOCK_REGS);
 
-	disable_pch_dp(dev_priv, pipe, PCH_DP_B);
-	disable_pch_dp(dev_priv, pipe, PCH_DP_C);
-	disable_pch_dp(dev_priv, pipe, PCH_DP_D);
+	disable_pch_dp(dev_priv, pipe, PCH_DP_B, TRANS_DP_PORT_SEL_B);
+	disable_pch_dp(dev_priv, pipe, PCH_DP_C, TRANS_DP_PORT_SEL_C);
+	disable_pch_dp(dev_priv, pipe, PCH_DP_D, TRANS_DP_PORT_SEL_D);
 
 	reg = PCH_ADPA;
 	val = I915_READ(reg);