Merge branch 'stable-3.2' into pandora-3.2

[pandora-kernel.git] / drivers / gpu / drm / i915 / intel_display.c

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index c7b5428..4a7d597 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -8699,9 +8699,15 @@ static void intel_init_display(struct drm_device *dev)
                if (IS_IVYBRIDGE(dev)) {
                        u32     ecobus;
 
+                       /* A small trick here - if the bios hasn't configured MT forcewake,
+                        * and if the device is in RC6, then force_wake_mt_get will not wake
+                        * the device and the ECOBUS read will return zero. Which will be
+                        * (correctly) interpreted by the test below as MT forcewake being
+                        * disabled.
+                        */
                        mutex_lock(&dev->struct_mutex);
                        __gen6_gt_force_wake_mt_get(dev_priv);
-                       ecobus = I915_READ(ECOBUS);
+                       ecobus = I915_READ_NOTRACE(ECOBUS);
                        __gen6_gt_force_wake_mt_put(dev_priv);
                        mutex_unlock(&dev->struct_mutex);