[PATCH 13/14] drm/i915: Filter gmch fifo underruns in the shared handler

[Daniel Vetter <daniel.vetter@ffwll.ch>]

This simplifies the code in the vlv irq handler. Also this now
means that we correctly filter underruns on gen2-4.

And as the real upshot I need to document one less function for
the fifo underrun code.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
 drivers/gpu/drm/i915/i915_irq.c            | 6 +++---
 drivers/gpu/drm/i915/intel_drv.h           | 2 --
 drivers/gpu/drm/i915/intel_fifo_underrun.c | 9 +++++++--
 3 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 27aa43672d5c..baa2a0a9cc92 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -1771,9 +1771,9 @@ static void valleyview_pipestat_irq_handler(struct drm_device *dev, u32 iir)
 		 * we need to be careful that we only handle what we want to
 		 * handle.
 		 */
-		mask = 0;
-		if (__cpu_fifo_underrun_reporting_enabled(dev_priv, pipe))
-			mask |= PIPE_FIFO_UNDERRUN_STATUS;
+
+		/* fifo underruns are filterered in the underrun handler. */
+		mask = PIPE_FIFO_UNDERRUN_STATUS;
 
 		switch (pipe) {
 		case PIPE_A:
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index c91737dbbc5d..91e2b128c537 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -754,8 +754,6 @@ void intel_cpu_fifo_underrun_irq_handler(struct drm_i915_private *dev_priv,
 void intel_pch_fifo_underrun_irq_handler(struct drm_i915_private *dev_priv,
 					 enum transcoder pch_transcoder);
 void i9xx_check_fifo_underruns(struct drm_i915_private *dev_priv);
-bool __cpu_fifo_underrun_reporting_enabled(struct drm_i915_private *dev_priv,
-					   enum pipe pipe);
 
 /* i915_irq.c */
 void gen5_enable_gt_irq(struct drm_i915_private *dev_priv, uint32_t mask);
diff --git a/drivers/gpu/drm/i915/intel_fifo_underrun.c b/drivers/gpu/drm/i915/intel_fifo_underrun.c
index 854d29e18555..02909259bfb6 100644
--- a/drivers/gpu/drm/i915/intel_fifo_underrun.c
+++ b/drivers/gpu/drm/i915/intel_fifo_underrun.c
@@ -252,8 +252,8 @@ bool intel_set_cpu_fifo_underrun_reporting(struct drm_i915_private *dev_priv,
 	return ret;
 }
 
-bool __cpu_fifo_underrun_reporting_enabled(struct drm_i915_private *dev_priv,
-					   enum pipe pipe)
+static bool __cpu_fifo_underrun_reporting_enabled(struct drm_i915_private *dev_priv,
+						  enum pipe pipe)
 {
 	struct drm_crtc *crtc = dev_priv->pipe_to_crtc_mapping[pipe];
 	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
@@ -312,6 +312,11 @@ bool intel_set_pch_fifo_underrun_reporting(struct drm_i915_private *dev_priv,
 void intel_cpu_fifo_underrun_irq_handler(struct drm_i915_private *dev_priv,
 					 enum pipe pipe)
 {
+	/* GMCH can't disable fifo underruns, filter them. */
+	if (HAS_GMCH_DISPLAY(dev_priv->dev) &&
+	    !__cpu_fifo_underrun_reporting_enabled(dev_priv, pipe))
+		return;
+
 	if (intel_set_cpu_fifo_underrun_reporting(dev_priv, pipe, false))
 		DRM_ERROR("CPU pipe %c FIFO underrun\n",
 			  pipe_name(pipe));
-- 
2.1.1