diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 074385882ccfe721ff5630b9e825950c6479af7e..43ce3809ef6419bdefa31e8731dae359e30836ca 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;