[Intel-gfx] [PATCH] drm/i915: Suppress warning for MTRR failure if PAT is enabled

[Chris Wilson]

Emitting a spurious warning about poor graphics performance when MTRR
are irrelevant leads to confused users and useless bug reports.

References: https://bugs.freedesktop.org/show_bug.cgi?id=41648
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_dma.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 716ba80..7a99d0c 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -35,6 +35,7 @@
 #include "i915_drv.h"
 #include "i915_trace.h"
 #include "../../../platform/x86/intel_ips.h"
+#include <asm/pat.h>
 #include <linux/pci.h>
 #include <linux/vgaarb.h>
 #include <linux/acpi.h>
@@ -1998,10 +1999,9 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
 	dev_priv->mm.gtt_mtrr = mtrr_add(dev->agp->base,
 					 agp_size,
 					 MTRR_TYPE_WRCOMB, 1);
-	if (dev_priv->mm.gtt_mtrr < 0) {
+	if (dev_priv->mm.gtt_mtrr < 0 && !pat_enabled)
 		DRM_INFO("MTRR allocation failed.  Graphics "
 			 "performance may suffer.\n");
-	}
 
 	/* The i915 workqueue is primarily used for batched retirement of
 	 * requests (and thus managing bo) once the task has been completed
-- 
1.7.9