diff options
Diffstat (limited to 'drivers/gpu/drm/i915/intel_display.c')
| -rw-r--r-- | drivers/gpu/drm/i915/intel_display.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index cb21d5bbeccb..ff99fa267bf6 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -8591,9 +8591,15 @@ 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); |
