[Intel-gfx] [PATCH 3/4] drm/i915: remove intel_uncore_check_errors()

[Paulo Zanoni]

I added this code on 8664281b64c457705db72fc60143d03827e75ca9, on
April 12 2013. Back then, we only had support for detecting unclaimed
registers on I915_WRITE operations, and we didn't have the
i915.mmio_debug infrastructure.

I tried to remember exactly why I added this code, and the only reason
I can think is: to help debugging. With this code, we would be able to
differentiate between the "your interrupt handler did something wrong"
and the "something bad happened before the interrupt handler" cases,
at the cost of one extra register read operation per interrupt.

Since then, we added unclaimed register checking support for
I915_READ, we added the i915.mmio_debug infrastructure and we also
fixed most (all?) of the unclaimed register problems on HSW. Due
to this, I don't think the extra register read at every interrupt is
necesary anymore: we're probably good in terms of debugging.

So let's kill this function in order to make sure it completely
disappears from perf.

Notice that this only affects HSW.

Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h     |  1 -
 drivers/gpu/drm/i915/i915_irq.c     |  4 ----
 drivers/gpu/drm/i915/intel_uncore.c | 11 -----------
 3 files changed, 16 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 1287007..194e864 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2703,7 +2703,6 @@ extern void intel_uncore_sanitize(struct drm_device *dev);
 extern void intel_uncore_early_sanitize(struct drm_device *dev,
 					bool restore_forcewake);
 extern void intel_uncore_init(struct drm_device *dev);
-extern void intel_uncore_check_errors(struct drm_device *dev);
 extern void intel_uncore_fini(struct drm_device *dev);
 extern void intel_uncore_forcewake_reset(struct drm_device *dev, bool restore);
 const char *intel_uncore_forcewake_domain_to_str(const enum forcewake_domain_id id);
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 2063279..57ec55e 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -2064,10 +2064,6 @@ static irqreturn_t ironlake_irq_handler(int irq, void *arg)
 	if (!intel_irqs_enabled(dev_priv))
 		return IRQ_NONE;
 
-	/* We get interrupts on unclaimed registers, so check for this before we
-	 * do any I915_{READ,WRITE}. */
-	intel_uncore_check_errors(dev);
-
 	/* disable master interrupt before clearing iir  */
 	de_ier = I915_READ(DEIER);
 	I915_WRITE(DEIER, de_ier & ~DE_MASTER_IRQ_CONTROL);
diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
index 65e0ea8..8844c314 100644
--- a/drivers/gpu/drm/i915/intel_uncore.c
+++ b/drivers/gpu/drm/i915/intel_uncore.c
@@ -1554,14 +1554,3 @@ bool intel_has_gpu_reset(struct drm_device *dev)
 {
 	return intel_get_gpu_reset(dev) != NULL;
 }
-
-void intel_uncore_check_errors(struct drm_device *dev)
-{
-	struct drm_i915_private *dev_priv = dev->dev_private;
-
-	if (HAS_FPGA_DBG_UNCLAIMED(dev) &&
-	    (__raw_i915_read32(dev_priv, FPGA_DBG) & FPGA_DBG_RM_NOCLAIM)) {
-		DRM_ERROR("Unclaimed register before interrupt\n");
-		__raw_i915_write32(dev_priv, FPGA_DBG, FPGA_DBG_RM_NOCLAIM);
-	}
-}
-- 
2.5.0