1 files changed, 10 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 074385882ccf..43ce3809ef64 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -4741,6 +4741,16 @@ i915_gem_load(struct drm_device *dev)
         list_add(&dev_priv->mm.shrink_list, &shrink_list);
         spin_unlock(&shrink_list_lock);
 
+        /* On GEN3 we really need to make sure the ARB C3 LP bit is set */
+        if (IS_GEN3(dev)) {
+                u32 tmp = I915_READ(MI_ARB_STATE);
+                if (!(tmp & MI_ARB_C3_LP_WRITE_ENABLE)) {
+                        /* arb state is a masked write, so set bit + bit in mask */
+                        tmp = MI_ARB_C3_LP_WRITE_ENABLE | (MI_ARB_C3_LP_WRITE_ENABLE << MI_ARB_MASK_SHIFT);
+                        I915_WRITE(MI_ARB_STATE, tmp);
+                }
+        }
+
         /* Old X drivers will take 0-2 for front, back, depth buffers */
         if (!drm_core_check_feature(dev, DRIVER_MODESET))
                 dev_priv->fence_reg_start = 3;