drm/i915: Extract intel_fifo_underrun.c

Prep work for some nice documentation. Requires that we export the
display irq enable/disable functions on ilk/ibx. But we already export
them for vlv/i915. So not more inconsistency.

v2: Rebase on top of skl stage 1.

Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

drivers/gpu/drm/i915/Makefile

@@ -45,6 +45,7 @@ i915-y += intel_renderstate_gen6.o \
 # modesetting core code
 i915-y += intel_bios.o \
 	  intel_display.o \
+	  intel_fifo_underrun.o \
 	  intel_frontbuffer.o \
 	  intel_modes.o \
 	  intel_overlay.o \

drivers/gpu/drm/i915/i915_drv.h

@@ -2312,6 +2312,17 @@ i915_disable_pipestat(struct drm_i915_private *dev_priv, enum pipe pipe,
 
 void valleyview_enable_display_irqs(struct drm_i915_private *dev_priv);
 void valleyview_disable_display_irqs(struct drm_i915_private *dev_priv);
+void
+ironlake_enable_display_irq(struct drm_i915_private *dev_priv, u32 mask);
+void
+ironlake_disable_display_irq(struct drm_i915_private *dev_priv, u32 mask);
+void ibx_display_interrupt_update(struct drm_i915_private *dev_priv,
+				  uint32_t interrupt_mask,
+				  uint32_t enabled_irq_mask);
+#define ibx_enable_display_interrupt(dev_priv, bits) \
+	ibx_display_interrupt_update((dev_priv), (bits), (bits))
+#define ibx_disable_display_interrupt(dev_priv, bits) \
+	ibx_display_interrupt_update((dev_priv), (bits), 0)
 
 /* i915_gem.c */
 int i915_gem_init_ioctl(struct drm_device *dev, void *data,

drivers/gpu/drm/i915/i915_irq.c

@@ -139,7 +139,7 @@ static const u32 hpd_status_i915[] = { /* i915 and valleyview are the same */
 } while (0)
 
 /* For display hotplug interrupt */
-static void
+void
 ironlake_enable_display_irq(struct drm_i915_private *dev_priv, u32 mask)
 {
 	assert_spin_locked(&dev_priv->irq_lock);
@@ -154,7 +154,7 @@ ironlake_enable_display_irq(struct drm_i915_private *dev_priv, u32 mask)
 	}
 }
 
-static void
+void
 ironlake_disable_display_irq(struct drm_i915_private *dev_priv, u32 mask)
 {
 	assert_spin_locked(&dev_priv->irq_lock);
@@ -238,24 +238,6 @@ void gen6_disable_pm_irq(struct drm_i915_private *dev_priv, uint32_t mask)
 	snb_update_pm_irq(dev_priv, mask, 0);
 }
 
-static bool ivb_can_enable_err_int(struct drm_device *dev)
-{
-	struct drm_i915_private *dev_priv = dev->dev_private;
-	struct intel_crtc *crtc;
-	enum pipe pipe;
-
-	assert_spin_locked(&dev_priv->irq_lock);
-
-	for_each_pipe(dev_priv, pipe) {
-		crtc = to_intel_crtc(dev_priv->pipe_to_crtc_mapping[pipe]);
-
-		if (crtc->cpu_fifo_underrun_disabled)
-			return false;
-	}
-
-	return true;
-}
-
 /**
   * bdw_update_pm_irq - update GT interrupt 2
   * @dev_priv: driver private
@@ -296,130 +278,15 @@ void gen8_disable_pm_irq(struct drm_i915_private *dev_priv, uint32_t mask)
 	bdw_update_pm_irq(dev_priv, mask, 0);
 }
 
-static bool cpt_can_enable_serr_int(struct drm_device *dev)
-{
-	struct drm_i915_private *dev_priv = dev->dev_private;
-	enum pipe pipe;
-	struct intel_crtc *crtc;
-
-	assert_spin_locked(&dev_priv->irq_lock);
-
-	for_each_pipe(dev_priv, pipe) {
-		crtc = to_intel_crtc(dev_priv->pipe_to_crtc_mapping[pipe]);
-
-		if (crtc->pch_fifo_underrun_disabled)
-			return false;
-	}
-
-	return true;
-}
-
-void i9xx_check_fifo_underruns(struct drm_device *dev)
-{
-	struct drm_i915_private *dev_priv = dev->dev_private;
-	struct intel_crtc *crtc;
-
-	spin_lock_irq(&dev_priv->irq_lock);
-
-	for_each_intel_crtc(dev, crtc) {
-		u32 reg = PIPESTAT(crtc->pipe);
-		u32 pipestat;
-
-		if (crtc->cpu_fifo_underrun_disabled)
-			continue;
-
-		pipestat = I915_READ(reg) & 0xffff0000;
-		if ((pipestat & PIPE_FIFO_UNDERRUN_STATUS) == 0)
-			continue;
-
-		I915_WRITE(reg, pipestat | PIPE_FIFO_UNDERRUN_STATUS);
-		POSTING_READ(reg);
-
-		DRM_ERROR("pipe %c underrun\n", pipe_name(crtc->pipe));
-	}
-
-	spin_unlock_irq(&dev_priv->irq_lock);
-}
-
-static void i9xx_set_fifo_underrun_reporting(struct drm_device *dev,
-					     enum pipe pipe,
-					     bool enable, bool old)
-{
-	struct drm_i915_private *dev_priv = dev->dev_private;
-	u32 reg = PIPESTAT(pipe);
-	u32 pipestat = I915_READ(reg) & 0xffff0000;
-
-	assert_spin_locked(&dev_priv->irq_lock);
-
-	if (enable) {
-		I915_WRITE(reg, pipestat | PIPE_FIFO_UNDERRUN_STATUS);
-		POSTING_READ(reg);
-	} else {
-		if (old && pipestat & PIPE_FIFO_UNDERRUN_STATUS)
-			DRM_ERROR("pipe %c underrun\n", pipe_name(pipe));
-	}
-}
-
-static void ironlake_set_fifo_underrun_reporting(struct drm_device *dev,
-						 enum pipe pipe, bool enable)
-{
-	struct drm_i915_private *dev_priv = dev->dev_private;
-	uint32_t bit = (pipe == PIPE_A) ? DE_PIPEA_FIFO_UNDERRUN :
-					  DE_PIPEB_FIFO_UNDERRUN;
-
-	if (enable)
-		ironlake_enable_display_irq(dev_priv, bit);
-	else
-		ironlake_disable_display_irq(dev_priv, bit);
-}
-
-static void ivybridge_set_fifo_underrun_reporting(struct drm_device *dev,
-						  enum pipe pipe,
-						  bool enable, bool old)
-{
-	struct drm_i915_private *dev_priv = dev->dev_private;
-	if (enable) {
-		I915_WRITE(GEN7_ERR_INT, ERR_INT_FIFO_UNDERRUN(pipe));
-
-		if (!ivb_can_enable_err_int(dev))
-			return;
-
-		ironlake_enable_display_irq(dev_priv, DE_ERR_INT_IVB);
-	} else {
-		ironlake_disable_display_irq(dev_priv, DE_ERR_INT_IVB);
-
-		if (old &&
-		    I915_READ(GEN7_ERR_INT) & ERR_INT_FIFO_UNDERRUN(pipe)) {
-			DRM_ERROR("uncleared fifo underrun on pipe %c\n",
-				  pipe_name(pipe));
-		}
-	}
-}
-
-static void broadwell_set_fifo_underrun_reporting(struct drm_device *dev,
-						  enum pipe pipe, bool enable)
-{
-	struct drm_i915_private *dev_priv = dev->dev_private;
-
-	assert_spin_locked(&dev_priv->irq_lock);
-
-	if (enable)
-		dev_priv->de_irq_mask[pipe] &= ~GEN8_PIPE_FIFO_UNDERRUN;
-	else
-		dev_priv->de_irq_mask[pipe] |= GEN8_PIPE_FIFO_UNDERRUN;
-	I915_WRITE(GEN8_DE_PIPE_IMR(pipe), dev_priv->de_irq_mask[pipe]);
-	POSTING_READ(GEN8_DE_PIPE_IMR(pipe));
-}
-
 /**
  * ibx_display_interrupt_update - update SDEIMR
  * @dev_priv: driver private
  * @interrupt_mask: mask of interrupt bits to update
  * @enabled_irq_mask: mask of interrupt bits to enable
  */
-static void ibx_display_interrupt_update(struct drm_i915_private *dev_priv,
-					 uint32_t interrupt_mask,
-					 uint32_t enabled_irq_mask)
+void ibx_display_interrupt_update(struct drm_i915_private *dev_priv,
+				  uint32_t interrupt_mask,
+				  uint32_t enabled_irq_mask)
 {
 	uint32_t sdeimr = I915_READ(SDEIMR);
 	sdeimr &= ~interrupt_mask;
@@ -433,160 +300,6 @@ static void ibx_display_interrupt_update(struct drm_i915_private *dev_priv,
 	I915_WRITE(SDEIMR, sdeimr);
 	POSTING_READ(SDEIMR);
 }
-#define ibx_enable_display_interrupt(dev_priv, bits) \
-	ibx_display_interrupt_update((dev_priv), (bits), (bits))
-#define ibx_disable_display_interrupt(dev_priv, bits) \
-	ibx_display_interrupt_update((dev_priv), (bits), 0)
-
-static void ibx_set_fifo_underrun_reporting(struct drm_device *dev,
-					    enum transcoder pch_transcoder,
-					    bool enable)
-{
-	struct drm_i915_private *dev_priv = dev->dev_private;
-	uint32_t bit = (pch_transcoder == TRANSCODER_A) ?
-		       SDE_TRANSA_FIFO_UNDER : SDE_TRANSB_FIFO_UNDER;
-
-	if (enable)
-		ibx_enable_display_interrupt(dev_priv, bit);
-	else
-		ibx_disable_display_interrupt(dev_priv, bit);
-}
-
-static void cpt_set_fifo_underrun_reporting(struct drm_device *dev,
-					    enum transcoder pch_transcoder,
-					    bool enable, bool old)
-{
-	struct drm_i915_private *dev_priv = dev->dev_private;
-
-	if (enable) {
-		I915_WRITE(SERR_INT,
-			   SERR_INT_TRANS_FIFO_UNDERRUN(pch_transcoder));
-
-		if (!cpt_can_enable_serr_int(dev))
-			return;
-
-		ibx_enable_display_interrupt(dev_priv, SDE_ERROR_CPT);
-	} else {
-		ibx_disable_display_interrupt(dev_priv, SDE_ERROR_CPT);
-
-		if (old && I915_READ(SERR_INT) &
-		    SERR_INT_TRANS_FIFO_UNDERRUN(pch_transcoder)) {
-			DRM_ERROR("uncleared pch fifo underrun on pch transcoder %c\n",
-				  transcoder_name(pch_transcoder));
-		}
-	}
-}
-
-/**
- * intel_set_cpu_fifo_underrun_reporting - enable/disable FIFO underrun messages
- * @dev: drm device
- * @pipe: pipe
- * @enable: true if we want to report FIFO underrun errors, false otherwise
- *
- * This function makes us disable or enable CPU fifo underruns for a specific
- * pipe. Notice that on some Gens (e.g. IVB, HSW), disabling FIFO underrun
- * reporting for one pipe may also disable all the other CPU error interruts for
- * the other pipes, due to the fact that there's just one interrupt mask/enable
- * bit for all the pipes.
- *
- * Returns the previous state of underrun reporting.
- */
-static bool __intel_set_cpu_fifo_underrun_reporting(struct drm_device *dev,
-						    enum pipe pipe, bool enable)
-{
-	struct drm_i915_private *dev_priv = dev->dev_private;
-	struct drm_crtc *crtc = dev_priv->pipe_to_crtc_mapping[pipe];
-	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
-	bool old;
-
-	assert_spin_locked(&dev_priv->irq_lock);
-
-	old = !intel_crtc->cpu_fifo_underrun_disabled;
-	intel_crtc->cpu_fifo_underrun_disabled = !enable;
-
-	if (HAS_GMCH_DISPLAY(dev))
-		i9xx_set_fifo_underrun_reporting(dev, pipe, enable, old);
-	else if (IS_GEN5(dev) || IS_GEN6(dev))
-		ironlake_set_fifo_underrun_reporting(dev, pipe, enable);
-	else if (IS_GEN7(dev))
-		ivybridge_set_fifo_underrun_reporting(dev, pipe, enable, old);
-	else if (IS_GEN8(dev) || IS_GEN9(dev))
-		broadwell_set_fifo_underrun_reporting(dev, pipe, enable);
-
-	return old;
-}
-
-bool intel_set_cpu_fifo_underrun_reporting(struct drm_device *dev,
-					   enum pipe pipe, bool enable)
-{
-	struct drm_i915_private *dev_priv = dev->dev_private;
-	unsigned long flags;
-	bool ret;
-
-	spin_lock_irqsave(&dev_priv->irq_lock, flags);
-	ret = __intel_set_cpu_fifo_underrun_reporting(dev, pipe, enable);
-	spin_unlock_irqrestore(&dev_priv->irq_lock, flags);
-
-	return ret;
-}
-
-static bool __cpu_fifo_underrun_reporting_enabled(struct drm_device *dev,
-						  enum pipe pipe)
-{
-	struct drm_i915_private *dev_priv = dev->dev_private;
-	struct drm_crtc *crtc = dev_priv->pipe_to_crtc_mapping[pipe];
-	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
-
-	return !intel_crtc->cpu_fifo_underrun_disabled;
-}
-
-/**
- * intel_set_pch_fifo_underrun_reporting - enable/disable FIFO underrun messages
- * @dev: drm device
- * @pch_transcoder: the PCH transcoder (same as pipe on IVB and older)
- * @enable: true if we want to report FIFO underrun errors, false otherwise
- *
- * This function makes us disable or enable PCH fifo underruns for a specific
- * PCH transcoder. Notice that on some PCHs (e.g. CPT/PPT), disabling FIFO
- * underrun reporting for one transcoder may also disable all the other PCH
- * error interruts for the other transcoders, due to the fact that there's just
- * one interrupt mask/enable bit for all the transcoders.
- *
- * Returns the previous state of underrun reporting.
- */
-bool intel_set_pch_fifo_underrun_reporting(struct drm_device *dev,
-					   enum transcoder pch_transcoder,
-					   bool enable)
-{
-	struct drm_i915_private *dev_priv = dev->dev_private;
-	struct drm_crtc *crtc = dev_priv->pipe_to_crtc_mapping[pch_transcoder];
-	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
-	unsigned long flags;
-	bool old;
-
-	/*
-	 * NOTE: Pre-LPT has a fixed cpu pipe -> pch transcoder mapping, but LPT
-	 * has only one pch transcoder A that all pipes can use. To avoid racy
-	 * pch transcoder -> pipe lookups from interrupt code simply store the
-	 * underrun statistics in crtc A. Since we never expose this anywhere
-	 * nor use it outside of the fifo underrun code here using the "wrong"
-	 * crtc on LPT won't cause issues.
-	 */
-
-	spin_lock_irqsave(&dev_priv->irq_lock, flags);
-
-	old = !intel_crtc->pch_fifo_underrun_disabled;
-	intel_crtc->pch_fifo_underrun_disabled = !enable;
-
-	if (HAS_PCH_IBX(dev))
-		ibx_set_fifo_underrun_reporting(dev, pch_transcoder, enable);
-	else
-		cpt_set_fifo_underrun_reporting(dev, pch_transcoder, enable, old);
-
-	spin_unlock_irqrestore(&dev_priv->irq_lock, flags);
-	return old;
-}
-
 
 static void
 __i915_enable_pipestat(struct drm_i915_private *dev_priv, enum pipe pipe,

drivers/gpu/drm/i915/intel_drv.h

@@ -755,12 +755,17 @@ static inline unsigned int intel_num_planes(struct intel_crtc *crtc)
 	return INTEL_INFO(crtc->base.dev)->num_sprites[crtc->pipe] + 1;
 }
 
-/* i915_irq.c */
+/* intel_fifo_underrun.c */
 bool intel_set_cpu_fifo_underrun_reporting(struct drm_device *dev,
 					   enum pipe pipe, bool enable);
 bool intel_set_pch_fifo_underrun_reporting(struct drm_device *dev,
 					   enum transcoder pch_transcoder,
 					   bool enable);
+void i9xx_check_fifo_underruns(struct drm_device *dev);
+bool __cpu_fifo_underrun_reporting_enabled(struct drm_device *dev,
+					   enum pipe pipe);
+
+/* i915_irq.c */
 void gen5_enable_gt_irq(struct drm_i915_private *dev_priv, uint32_t mask);
 void gen5_disable_gt_irq(struct drm_i915_private *dev_priv, uint32_t mask);
 void gen6_enable_pm_irq(struct drm_i915_private *dev_priv, uint32_t mask);
@@ -779,7 +784,6 @@ static inline bool intel_irqs_enabled(struct drm_i915_private *dev_priv)
 }
 
 int intel_get_crtc_scanline(struct intel_crtc *crtc);
-void i9xx_check_fifo_underruns(struct drm_device *dev);
 void gen8_irq_power_well_post_enable(struct drm_i915_private *dev_priv);
 
 /* intel_crt.c */

drivers/gpu/drm/i915/intel_fifo_underrun.c

@@ -0,0 +1,311 @@
+/*
+ * Copyright © 2014 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ * Authors:
+ *    Daniel Vetter <daniel.vetter@ffwll.ch>
+ *
+ */
+
+#include "i915_drv.h"
+#include "intel_drv.h"
+
+static bool ivb_can_enable_err_int(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_crtc *crtc;
+	enum pipe pipe;
+
+	assert_spin_locked(&dev_priv->irq_lock);
+
+	for_each_pipe(dev_priv, pipe) {
+		crtc = to_intel_crtc(dev_priv->pipe_to_crtc_mapping[pipe]);
+
+		if (crtc->cpu_fifo_underrun_disabled)
+			return false;
+	}
+
+	return true;
+}
+
+static bool cpt_can_enable_serr_int(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	enum pipe pipe;
+	struct intel_crtc *crtc;
+
+	assert_spin_locked(&dev_priv->irq_lock);
+
+	for_each_pipe(dev_priv, pipe) {
+		crtc = to_intel_crtc(dev_priv->pipe_to_crtc_mapping[pipe]);
+
+		if (crtc->pch_fifo_underrun_disabled)
+			return false;
+	}
+
+	return true;
+}
+
+void i9xx_check_fifo_underruns(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_crtc *crtc;
+
+	spin_lock_irq(&dev_priv->irq_lock);
+
+	for_each_intel_crtc(dev, crtc) {
+		u32 reg = PIPESTAT(crtc->pipe);
+		u32 pipestat;
+
+		if (crtc->cpu_fifo_underrun_disabled)
+			continue;
+
+		pipestat = I915_READ(reg) & 0xffff0000;
+		if ((pipestat & PIPE_FIFO_UNDERRUN_STATUS) == 0)
+			continue;
+
+		I915_WRITE(reg, pipestat | PIPE_FIFO_UNDERRUN_STATUS);
+		POSTING_READ(reg);
+
+		DRM_ERROR("pipe %c underrun\n", pipe_name(crtc->pipe));
+	}
+
+	spin_unlock_irq(&dev_priv->irq_lock);
+}
+
+static void i9xx_set_fifo_underrun_reporting(struct drm_device *dev,
+					     enum pipe pipe,
+					     bool enable, bool old)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	u32 reg = PIPESTAT(pipe);
+	u32 pipestat = I915_READ(reg) & 0xffff0000;
+
+	assert_spin_locked(&dev_priv->irq_lock);
+
+	if (enable) {
+		I915_WRITE(reg, pipestat | PIPE_FIFO_UNDERRUN_STATUS);
+		POSTING_READ(reg);
+	} else {
+		if (old && pipestat & PIPE_FIFO_UNDERRUN_STATUS)
+			DRM_ERROR("pipe %c underrun\n", pipe_name(pipe));
+	}
+}
+
+static void ironlake_set_fifo_underrun_reporting(struct drm_device *dev,
+						 enum pipe pipe, bool enable)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	uint32_t bit = (pipe == PIPE_A) ? DE_PIPEA_FIFO_UNDERRUN :
+					  DE_PIPEB_FIFO_UNDERRUN;
+
+	if (enable)
+		ironlake_enable_display_irq(dev_priv, bit);
+	else
+		ironlake_disable_display_irq(dev_priv, bit);
+}
+
+static void ivybridge_set_fifo_underrun_reporting(struct drm_device *dev,
+						  enum pipe pipe,
+						  bool enable, bool old)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	if (enable) {
+		I915_WRITE(GEN7_ERR_INT, ERR_INT_FIFO_UNDERRUN(pipe));
+
+		if (!ivb_can_enable_err_int(dev))
+			return;
+
+		ironlake_enable_display_irq(dev_priv, DE_ERR_INT_IVB);
+	} else {
+		ironlake_disable_display_irq(dev_priv, DE_ERR_INT_IVB);
+
+		if (old &&
+		    I915_READ(GEN7_ERR_INT) & ERR_INT_FIFO_UNDERRUN(pipe)) {
+			DRM_ERROR("uncleared fifo underrun on pipe %c\n",
+				  pipe_name(pipe));
+		}
+	}
+}
+
+static void broadwell_set_fifo_underrun_reporting(struct drm_device *dev,
+						  enum pipe pipe, bool enable)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	assert_spin_locked(&dev_priv->irq_lock);
+
+	if (enable)
+		dev_priv->de_irq_mask[pipe] &= ~GEN8_PIPE_FIFO_UNDERRUN;
+	else
+		dev_priv->de_irq_mask[pipe] |= GEN8_PIPE_FIFO_UNDERRUN;
+	I915_WRITE(GEN8_DE_PIPE_IMR(pipe), dev_priv->de_irq_mask[pipe]);
+	POSTING_READ(GEN8_DE_PIPE_IMR(pipe));
+}
+
+static void ibx_set_fifo_underrun_reporting(struct drm_device *dev,
+					    enum transcoder pch_transcoder,
+					    bool enable)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	uint32_t bit = (pch_transcoder == TRANSCODER_A) ?
+		       SDE_TRANSA_FIFO_UNDER : SDE_TRANSB_FIFO_UNDER;
+
+	if (enable)
+		ibx_enable_display_interrupt(dev_priv, bit);
+	else
+		ibx_disable_display_interrupt(dev_priv, bit);
+}
+
+static void cpt_set_fifo_underrun_reporting(struct drm_device *dev,
+					    enum transcoder pch_transcoder,
+					    bool enable, bool old)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	if (enable) {
+		I915_WRITE(SERR_INT,
+			   SERR_INT_TRANS_FIFO_UNDERRUN(pch_transcoder));
+
+		if (!cpt_can_enable_serr_int(dev))
+			return;
+
+		ibx_enable_display_interrupt(dev_priv, SDE_ERROR_CPT);
+	} else {
+		ibx_disable_display_interrupt(dev_priv, SDE_ERROR_CPT);
+
+		if (old && I915_READ(SERR_INT) &
+		    SERR_INT_TRANS_FIFO_UNDERRUN(pch_transcoder)) {
+			DRM_ERROR("uncleared pch fifo underrun on pch transcoder %c\n",
+				  transcoder_name(pch_transcoder));
+		}
+	}
+}
+
+/**
+ * intel_set_cpu_fifo_underrun_reporting - enable/disable FIFO underrun messages
+ * @dev: drm device
+ * @pipe: pipe
+ * @enable: true if we want to report FIFO underrun errors, false otherwise
+ *
+ * This function makes us disable or enable CPU fifo underruns for a specific
+ * pipe. Notice that on some Gens (e.g. IVB, HSW), disabling FIFO underrun
+ * reporting for one pipe may also disable all the other CPU error interruts for
+ * the other pipes, due to the fact that there's just one interrupt mask/enable
+ * bit for all the pipes.
+ *
+ * Returns the previous state of underrun reporting.
+ */
+static bool __intel_set_cpu_fifo_underrun_reporting(struct drm_device *dev,
+						    enum pipe pipe, bool enable)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct drm_crtc *crtc = dev_priv->pipe_to_crtc_mapping[pipe];
+	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
+	bool old;
+
+	assert_spin_locked(&dev_priv->irq_lock);
+
+	old = !intel_crtc->cpu_fifo_underrun_disabled;
+	intel_crtc->cpu_fifo_underrun_disabled = !enable;
+
+	if (HAS_GMCH_DISPLAY(dev))
+		i9xx_set_fifo_underrun_reporting(dev, pipe, enable, old);
+	else if (IS_GEN5(dev) || IS_GEN6(dev))
+		ironlake_set_fifo_underrun_reporting(dev, pipe, enable);
+	else if (IS_GEN7(dev))
+		ivybridge_set_fifo_underrun_reporting(dev, pipe, enable, old);
+	else if (IS_GEN8(dev) || IS_GEN9(dev))
+		broadwell_set_fifo_underrun_reporting(dev, pipe, enable);
+
+	return old;
+}
+
+bool intel_set_cpu_fifo_underrun_reporting(struct drm_device *dev,
+					   enum pipe pipe, bool enable)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	unsigned long flags;
+	bool ret;
+
+	spin_lock_irqsave(&dev_priv->irq_lock, flags);
+	ret = __intel_set_cpu_fifo_underrun_reporting(dev, pipe, enable);
+	spin_unlock_irqrestore(&dev_priv->irq_lock, flags);
+
+	return ret;
+}
+
+bool __cpu_fifo_underrun_reporting_enabled(struct drm_device *dev,
+					   enum pipe pipe)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct drm_crtc *crtc = dev_priv->pipe_to_crtc_mapping[pipe];
+	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
+
+	return !intel_crtc->cpu_fifo_underrun_disabled;
+}
+
+/**
+ * intel_set_pch_fifo_underrun_reporting - enable/disable FIFO underrun messages
+ * @dev: drm device
+ * @pch_transcoder: the PCH transcoder (same as pipe on IVB and older)
+ * @enable: true if we want to report FIFO underrun errors, false otherwise
+ *
+ * This function makes us disable or enable PCH fifo underruns for a specific
+ * PCH transcoder. Notice that on some PCHs (e.g. CPT/PPT), disabling FIFO
+ * underrun reporting for one transcoder may also disable all the other PCH
+ * error interruts for the other transcoders, due to the fact that there's just
+ * one interrupt mask/enable bit for all the transcoders.
+ *
+ * Returns the previous state of underrun reporting.
+ */
+bool intel_set_pch_fifo_underrun_reporting(struct drm_device *dev,
+					   enum transcoder pch_transcoder,
+					   bool enable)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct drm_crtc *crtc = dev_priv->pipe_to_crtc_mapping[pch_transcoder];
+	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
+	unsigned long flags;
+	bool old;
+
+	/*
+	 * NOTE: Pre-LPT has a fixed cpu pipe -> pch transcoder mapping, but LPT
+	 * has only one pch transcoder A that all pipes can use. To avoid racy
+	 * pch transcoder -> pipe lookups from interrupt code simply store the
+	 * underrun statistics in crtc A. Since we never expose this anywhere
+	 * nor use it outside of the fifo underrun code here using the "wrong"
+	 * crtc on LPT won't cause issues.
+	 */
+
+	spin_lock_irqsave(&dev_priv->irq_lock, flags);
+
+	old = !intel_crtc->pch_fifo_underrun_disabled;
+	intel_crtc->pch_fifo_underrun_disabled = !enable;
+
+	if (HAS_PCH_IBX(dev))
+		ibx_set_fifo_underrun_reporting(dev, pch_transcoder, enable);
+	else
+		cpt_set_fifo_underrun_reporting(dev, pch_transcoder, enable, old);
+
+	spin_unlock_irqrestore(&dev_priv->irq_lock, flags);
+	return old;
+}