diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 12c547a..e7cb5df 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -1444,6 +1444,7 @@
 #define   LVDS_PORT_EN			(1 << 31)
 /* Selects pipe B for LVDS data.  Must be set on pre-965. */
 #define   LVDS_PIPEB_SELECT		(1 << 30)
+#define   LVDS_PIPE_MASK		(1 << 30)
 /* LVDS dithering flag on 965/g4x platform */
 #define   LVDS_ENABLE_DITHER		(1 << 25)
 /* Enable border for unscaled (or aspect-scaled) display */
@@ -1479,6 +1480,9 @@
 #define   LVDS_B0B3_POWER_DOWN		(0 << 2)
 #define   LVDS_B0B3_POWER_UP		(3 << 2)
 
+#define LVDS_PIPE_ENABLED(V, P) \
+	(((V) & (LVDS_PIPE_MASK | LVDS_PORT_EN)) == ((P) << 30 | LVDS_PORT_EN))
+
 /* Video Data Island Packet control */
 #define VIDEO_DIP_DATA		0x61178
 #define VIDEO_DIP_CTL		0x61170
@@ -2067,6 +2071,10 @@
 
 #define   DP_PORT_EN			(1 << 31)
 #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)
@@ -3148,11 +3156,15 @@
 #define  ADPA_CRT_HOTPLUG_VOLREF_475MV  (1<<17)
 #define  ADPA_CRT_HOTPLUG_FORCE_TRIGGER (1<<16)
 
+#define ADPA_PIPE_ENABLED(V, P) \
+	(((V) & (ADPA_TRANS_SELECT_MASK | ADPA_DAC_ENABLE)) == ((P) << 30 | ADPA_DAC_ENABLE))
+
 /* or SDVOB */
 #define HDMIB   0xe1140
 #define  PORT_ENABLE    (1 << 31)
 #define  TRANSCODER_A   (0)
 #define  TRANSCODER_B   (1 << 30)
+#define  TRANSCODER_MASK   (1 << 30)
 #define  COLOR_FORMAT_8bpc      (0)
 #define  COLOR_FORMAT_12bpc     (3 << 26)
 #define  SDVOB_HOTPLUG_ENABLE   (1 << 23)
@@ -3168,6 +3180,9 @@
 #define  HSYNC_ACTIVE_HIGH      (1 << 3)
 #define  PORT_DETECTED          (1 << 2)
 
+#define HDMI_PIPE_ENABLED(V, P) \
+	(((V) & (TRANSCODER_MASK | PORT_ENABLE)) == ((P) << 30 | PORT_ENABLE))
+
 /* PCH SDVOB multiplex with HDMIB */
 #define PCH_SDVOB	HDMIB
 
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 841558b..88dc3fe 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1058,6 +1058,53 @@ void intel_wait_for_pipe_off(struct drm_device *dev, int pipe)
 	}
 }
 
+static void disable_pch_dp(struct drm_i915_private *dev_priv,
+			   enum pipe pipe, int reg)
+{
+	u32 val = I915_READ(reg);
+	if (DP_PIPE_ENABLED(val, 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))
+		I915_WRITE(reg, val & ~PORT_ENABLE);
+}
+
+/* Disable any ports connected to this transcoder */
+static void intel_disable_pch_ports(struct drm_i915_private *dev_priv,
+				    enum pipe pipe)
+{
+	u32 reg, val;
+
+	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);
+
+	reg = PCH_ADPA;
+	val = I915_READ(reg);
+	if (ADPA_PIPE_ENABLED(val, pipe))
+		I915_WRITE(reg, val & ~ADPA_DAC_ENABLE);
+
+	reg = PCH_LVDS;
+	val = I915_READ(reg);
+	if (LVDS_PIPE_ENABLED(val, pipe)) {
+		I915_WRITE(reg, val & ~LVDS_PORT_EN);
+		POSTING_READ(reg);
+		udelay(100);
+	}
+
+	disable_pch_hdmi(dev_priv, pipe, HDMIB);
+	disable_pch_hdmi(dev_priv, pipe, HDMIC);
+	disable_pch_hdmi(dev_priv, pipe, HDMID);
+}
+
 static void i8xx_enable_fbc(struct drm_crtc *crtc, unsigned long interval)
 {
 	struct drm_device *dev = crtc->dev;
@@ -2356,14 +2403,12 @@ static void ironlake_crtc_disable(struct drm_crtc *crtc)
 	POSTING_READ(reg);
 	udelay(100);
 
-	if (intel_pipe_has_type(crtc, INTEL_OUTPUT_LVDS)) {
-		temp = I915_READ(PCH_LVDS);
-		if (temp & LVDS_PORT_EN) {
-			I915_WRITE(PCH_LVDS, temp & ~LVDS_PORT_EN);
-			POSTING_READ(PCH_LVDS);
-			udelay(100);
-		}
-	}
+	/* This is a horrible layering violation; we should be doing this in
+	 * the connector/encoder ->prepare instead, but we don't always have
+	 * enough information there about the config to know whether it will
+	 * actually be necessary or just cause undesired flicker.
+	 */
+	intel_disable_pch_ports(dev_priv, pipe);
 
 	/* disable PCH transcoder */
 	reg = TRANSCONF(plane);
