[PATCH 08/10] drm/i915: print PCH FIFO underrun interrupts

[Paulo Zanoni <przanoni@gmail.com>]

From: Paulo Zanoni <paulo.r.zanoni@intel.com>

Also add an "ignore" bit that avoids printing the message in two
cases:
  - When the message is in fact expected.
  - After we get the first message. In tihs case, we expect to get
    hundreds of consecutive messages, so we just ignore all the
    subsequent messages until the next crtc_enable.

Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h      |    3 +++
 drivers/gpu/drm/i915/i915_irq.c      |   37 +++++++++++++++++++++++++++++-----
 drivers/gpu/drm/i915/i915_reg.h      |    7 +++++--
 drivers/gpu/drm/i915/intel_display.c |   14 ++++++++++++-
 4 files changed, 53 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 08c5def..e96d75e 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -909,6 +909,9 @@ typedef struct drm_i915_private {
 	struct work_struct hotplug_work;
 	bool enable_hotplug_processing;
 
+	/* Bit 0: PCH transcoder A and so on. */
+	u8 ignore_pch_fifo_underrun;
+
 	int num_pipe;
 	int num_pch_pll;
 
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 703a08a..7497589 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -659,10 +659,17 @@ static void ibx_irq_handler(struct drm_device *dev, u32 pch_iir)
 	if (pch_iir & (SDE_TRANSB_CRC_ERR | SDE_TRANSA_CRC_ERR))
 		DRM_DEBUG_DRIVER("PCH transcoder CRC error interrupt\n");
 
-	if (pch_iir & SDE_TRANSB_FIFO_UNDER)
-		DRM_DEBUG_DRIVER("PCH transcoder B underrun interrupt\n");
-	if (pch_iir & SDE_TRANSA_FIFO_UNDER)
-		DRM_DEBUG_DRIVER("PCH transcoder A underrun interrupt\n");
+	if ((pch_iir & SDE_TRANSB_FIFO_UNDER) &&
+	    !(dev_priv->ignore_pch_fifo_underrun & (1 << TRANSCODER_B))) {
+		DRM_DEBUG_DRIVER("PCH transcoder B underrun\n");
+		dev_priv->ignore_pch_fifo_underrun |= (1 << TRANSCODER_B);
+	}
+
+	if ((pch_iir & SDE_TRANSA_FIFO_UNDER) &&
+	    !(dev_priv->ignore_pch_fifo_underrun & (1 << TRANSCODER_A))) {
+		DRM_DEBUG_DRIVER("PCH transcoder A underrun\n");
+		dev_priv->ignore_pch_fifo_underrun |= (1 << TRANSCODER_A);
+	}
 }
 
 static void err_int_handler(struct drm_device *dev)
@@ -684,6 +691,24 @@ static void serr_int_handler(struct drm_device *dev)
 	if (serr_int & SERR_INT_POISON)
 		DRM_ERROR("PCH poison interrupt\n");
 
+	if ((serr_int & SERR_INT_TRANS_A_FIFO_UNDERRUN) &&
+	    !(dev_priv->ignore_pch_fifo_underrun & (1 << TRANSCODER_A))) {
+		DRM_ERROR("PCH transcoder A FIFO underrun\n");
+		dev_priv->ignore_pch_fifo_underrun |= (1 << TRANSCODER_A);
+	}
+
+	if ((serr_int & SERR_INT_TRANS_B_FIFO_UNDERRUN) &&
+	    !(dev_priv->ignore_pch_fifo_underrun & (1 << TRANSCODER_B))) {
+		DRM_ERROR("PCH transcoder B FIFO underrun\n");
+		dev_priv->ignore_pch_fifo_underrun |= (1 << TRANSCODER_B);
+	}
+
+	if ((serr_int & SERR_INT_TRANS_C_FIFO_UNDERRUN) &&
+	    !(dev_priv->ignore_pch_fifo_underrun & (1 << TRANSCODER_C))) {
+		DRM_ERROR("PCH transcoder C FIFO underrun\n");
+		dev_priv->ignore_pch_fifo_underrun |= (1 << TRANSCODER_C);
+	}
+
 	I915_WRITE(SERR_INT, serr_int);
 }
 
@@ -2000,7 +2025,9 @@ static void ibx_irq_postinstall(struct drm_device *dev)
 		mask = SDE_HOTPLUG_MASK |
 		       SDE_GMBUS |
 		       SDE_AUX_MASK |
-		       SDE_POISON;
+		       SDE_POISON |
+		       SDE_TRANSB_FIFO_UNDER |
+		       SDE_TRANSA_FIFO_UNDER;
 	} else {
 		mask = SDE_HOTPLUG_MASK_CPT |
 		       SDE_GMBUS_CPT |
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index f22e27d..d565bd7 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -3554,8 +3554,11 @@
 #define SDEIIR  0xc4008
 #define SDEIER  0xc400c
 
-#define SERR_INT		0xc4040
-#define  SERR_INT_POISON	(1 << 31)
+#define SERR_INT			0xc4040
+#define  SERR_INT_POISON		(1 << 31)
+#define  SERR_INT_TRANS_C_FIFO_UNDERRUN	(1 << 6)
+#define  SERR_INT_TRANS_B_FIFO_UNDERRUN	(1 << 3)
+#define  SERR_INT_TRANS_A_FIFO_UNDERRUN	(1 << 0)
 
 /* digital port hotplug */
 #define PCH_PORT_HOTPLUG        0xc4030		/* SHOTPLUG_CTL */
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index d75c6a0..67bfb58 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -3274,6 +3274,9 @@ static void ironlake_crtc_enable(struct drm_crtc *crtc)
 		return;
 
 	intel_crtc->active = true;
+
+	dev_priv->ignore_pch_fifo_underrun &= ~(1 << pipe);
+
 	intel_update_watermarks(dev);
 
 	if (intel_pipe_has_type(crtc, INTEL_OUTPUT_LVDS)) {
@@ -3366,11 +3369,15 @@ static void haswell_crtc_enable(struct drm_crtc *crtc)
 		return;
 
 	intel_crtc->active = true;
-	intel_update_watermarks(dev);
 
 	is_pch_port = haswell_crtc_driving_pch(crtc);
 
 	if (is_pch_port)
+		dev_priv->ignore_pch_fifo_underrun &= ~(1 << TRANSCODER_A);
+
+	intel_update_watermarks(dev);
+
+	if (is_pch_port)
 		dev_priv->display.fdi_link_train(crtc);
 
 	for_each_encoder_on_crtc(dev, crtc, encoder)
@@ -3453,6 +3460,7 @@ static void ironlake_crtc_disable(struct drm_crtc *crtc)
 	if (dev_priv->cfb_plane == plane)
 		intel_disable_fbc(dev);
 
+	dev_priv->ignore_pch_fifo_underrun |= (1 << pipe);
 	intel_disable_pipe(dev_priv, pipe);
 
 	/* Disable PF */
@@ -3466,6 +3474,7 @@ static void ironlake_crtc_disable(struct drm_crtc *crtc)
 	ironlake_fdi_disable(crtc);
 
 	ironlake_disable_pch_transcoder(dev_priv, pipe);
+	dev_priv->ignore_pch_fifo_underrun &= ~(1 << pipe);
 
 	if (HAS_PCH_CPT(dev)) {
 		/* disable TRANS_DP_CTL */
@@ -3535,6 +3544,8 @@ static void haswell_crtc_disable(struct drm_crtc *crtc)
 	if (dev_priv->cfb_plane == plane)
 		intel_disable_fbc(dev);
 
+	if (is_pch_port)
+		dev_priv->ignore_pch_fifo_underrun |= (1 << TRANSCODER_A);
 	intel_disable_pipe(dev_priv, pipe);
 
 	intel_ddi_disable_transcoder_func(dev_priv, cpu_transcoder);
@@ -3551,6 +3562,7 @@ static void haswell_crtc_disable(struct drm_crtc *crtc)
 
 	if (is_pch_port) {
 		lpt_disable_pch_transcoder(dev_priv);
+		dev_priv->ignore_pch_fifo_underrun &= ~(1 << TRANSCODER_A);
 		intel_ddi_fdi_disable(crtc);
 	}
 
-- 
1.7.10.4