[PATCH 06/14] drm/i915: Check for FIFO underruns after modeset on IVB/HSW and CPT/PPT

ville.syrjala
2015-10-29T19:26:33Z

From: Ville Syrjälä <ville.syrjala@linux.intel.com>

Due to the shared error interrupt on IVB/HSW and CPT/PPT we may not
always get an interrupt on a FIFO underrun. But we can always do an
explicit check (like we do on GMCH platforms that have no underrun
interrupt).

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
drivers/gpu/drm/i915/intel_display.c | 6 +-
drivers/gpu/drm/i915/intel_drv.h | 3 +-
drivers/gpu/drm/i915/intel_fifo_underrun.c | 121 ++++++++++++++++++++++++-----
3 files changed, 105 insertions(+), 25 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index c7cd9f7..e820147 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -4719,9 +4719,9 @@ intel_post_enable_primary(struct drm_crtc *crtc)
if (IS_GEN2(dev))
intel_set_cpu_fifo_underrun_reporting(dev_priv, pipe, true);

- /* Underruns don't raise interrupts, so check manually. */
- if (HAS_GMCH_DISPLAY(dev))
- i9xx_check_fifo_underruns(dev_priv);
+ /* Underruns don't always raise interrupts, so check manually. */
+ intel_check_cpu_fifo_underruns(dev_priv);
+ intel_check_pch_fifo_underruns(dev_priv);
}

/**
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 1a3bbdc..72cc272 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -959,7 +959,8 @@ void intel_cpu_fifo_underrun_irq_handler(struct drm_i915_private *dev_priv,
enum pipe pipe);
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);
+void intel_check_cpu_fifo_underruns(struct drm_i915_private *dev_priv);
+void intel_check_pch_fifo_underruns(struct drm_i915_private *dev_priv);

/* 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 54daa66..a546fc3 100644
--- a/drivers/gpu/drm/i915/intel_fifo_underrun.c
+++ b/drivers/gpu/drm/i915/intel_fifo_underrun.c
@@ -85,37 +85,28 @@ static bool cpt_can_enable_serr_int(struct drm_device *dev)
}

/**
- * i9xx_check_fifo_underruns - check for fifo underruns
- * @dev_priv: i915 device instance
+ * intel_check_cpu_fifo_underruns - check for fifo underruns
+ * @crtc: pipe
*
* This function checks for fifo underruns on GMCH platforms. This needs to be
* done manually on modeset to make sure that we catch all underruns since they
* do not generate an interrupt by themselves on these platforms.
*/
-void i9xx_check_fifo_underruns(struct drm_i915_private *dev_priv)
+static void i9xx_check_fifo_underruns(struct intel_crtc *crtc)
{
- struct intel_crtc *crtc;
-
- spin_lock_irq(&dev_priv->irq_lock);
-
- for_each_intel_crtc(dev_priv->dev, crtc) {
- u32 reg = PIPESTAT(crtc->pipe);
- u32 pipestat;
-
- if (crtc->cpu_fifo_underrun_disabled)
- continue;
+ struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
+ u32 reg = PIPESTAT(crtc->pipe);
+ u32 pipestat = I915_READ(reg) & 0xffff0000;

- pipestat = I915_READ(reg) & 0xffff0000;
- if ((pipestat & PIPE_FIFO_UNDERRUN_STATUS) == 0)
- continue;
+ assert_spin_locked(&dev_priv->irq_lock);

- I915_WRITE(reg, pipestat | PIPE_FIFO_UNDERRUN_STATUS);
- POSTING_READ(reg);
+ if ((pipestat & PIPE_FIFO_UNDERRUN_STATUS) == 0)
+ return;

- DRM_ERROR("pipe %c underrun\n", pipe_name(crtc->pipe));
- }
+ I915_WRITE(reg, pipestat | PIPE_FIFO_UNDERRUN_STATUS);
+ POSTING_READ(reg);

- spin_unlock_irq(&dev_priv->irq_lock);
+ DRM_ERROR("pipe %c underrun\n", pipe_name(crtc->pipe));
}

static void i9xx_set_fifo_underrun_reporting(struct drm_device *dev,
@@ -150,6 +141,23 @@ static void ironlake_set_fifo_underrun_reporting(struct drm_device *dev,
ironlake_disable_display_irq(dev_priv, bit);
}

+static void ivybridge_check_fifo_underruns(struct intel_crtc *crtc)
+{
+ struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
+ enum pipe pipe = crtc->pipe;
+ uint32_t err_int = I915_READ(GEN7_ERR_INT);
+
+ assert_spin_locked(&dev_priv->irq_lock);
+
+ if ((err_int & ERR_INT_FIFO_UNDERRUN(pipe)) == 0)
+ return;
+
+ I915_WRITE(GEN7_ERR_INT, ERR_INT_FIFO_UNDERRUN(pipe));
+ POSTING_READ(GEN7_ERR_INT);
+
+ DRM_ERROR("fifo underrun on pipe %c\n", pipe_name(pipe));
+}
+
static void ivybridge_set_fifo_underrun_reporting(struct drm_device *dev,
enum pipe pipe,
bool enable, bool old)
@@ -202,6 +210,24 @@ static void ibx_set_fifo_underrun_reporting(struct drm_device *dev,
ibx_disable_display_interrupt(dev_priv, bit);
}

+static void cpt_check_pch_fifo_underruns(struct intel_crtc *crtc)
+{
+ struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
+ enum transcoder pch_transcoder = (enum transcoder) crtc->pipe;
+ uint32_t serr_int = I915_READ(SERR_INT);
+
+ assert_spin_locked(&dev_priv->irq_lock);
+
+ if ((serr_int & SERR_INT_TRANS_FIFO_UNDERRUN(pch_transcoder)) == 0)
+ return;
+
+ I915_WRITE(SERR_INT, SERR_INT_TRANS_FIFO_UNDERRUN(pch_transcoder));
+ POSTING_READ(SERR_INT);
+
+ DRM_ERROR("pch fifo underrun on pch transcoder %c\n",
+ transcoder_name(pch_transcoder));
+}
+
static void cpt_set_fifo_underrun_reporting(struct drm_device *dev,
enum transcoder pch_transcoder,
bool enable, bool old)
@@ -375,3 +401,56 @@ void intel_pch_fifo_underrun_irq_handler(struct drm_i915_private *dev_priv,
DRM_ERROR("PCH transcoder %c FIFO underrun\n",
transcoder_name(pch_transcoder));
}
+
+/**
+ * intel_check_cpu_fifo_underruns - check for CPU fifo underruns immediately
+ * @dev_priv: i915 device instance
+ *
+ * Check for CPU fifo underruns immediately. Useful on IVB/HSW where the shared
+ * error interrupt may have been disabled, and so CPU fifo underruns won't
+ * necessarily raise an interrupt, and on GMCH platforms where underruns never
+ * raise an interrupt.
+ */
+void intel_check_cpu_fifo_underruns(struct drm_i915_private *dev_priv)
+{
+ struct intel_crtc *crtc;
+
+ spin_lock_irq(&dev_priv->irq_lock);
+
+ for_each_intel_crtc(dev_priv->dev, crtc) {
+ if (crtc->cpu_fifo_underrun_disabled)
+ continue;
+
+ if (HAS_GMCH_DISPLAY(dev_priv))
+ i9xx_check_fifo_underruns(crtc);
+ else if (IS_GEN7(dev_priv))
+ ivybridge_check_fifo_underruns(crtc);
+ }
+
+ spin_unlock_irq(&dev_priv->irq_lock);
+}
+
+/**
+ * intel_check_pch_fifo_underruns - check for PCH fifo underruns immediately
+ * @dev_priv: i915 device instance
+ *
+ * Check for PCH fifo underruns immediately. Useful on CPT/PPT where the shared
+ * error interrupt may have been disabled, and so PCH fifo underruns won't
+ * necessarily raise an interrupt.
+ */
+void intel_check_pch_fifo_underruns(struct drm_i915_private *dev_priv)
+{
+ struct intel_crtc *crtc;
+
+ spin_lock_irq(&dev_priv->irq_lock);
+
+ for_each_intel_crtc(dev_priv->dev, crtc) {
+ if (crtc->pch_fifo_underrun_disabled)
+ continue;
+
+ if (HAS_PCH_CPT(dev_priv))
+ cpt_check_pch_fifo_underruns(crtc);
+ }
+
+ spin_unlock_irq(&dev_priv->irq_lock);
+}
--
2.4.10