drm/i915: Enable MI_FLUSH on Sandybridge

MI_FLUSH is being deprecated, but still available on Sandybridge.
Make sure it's enabled as userspace still uses MI_FLUSH.

Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: stable@kernel.org
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

2 files changed, 7 insertions, 2 deletions

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 67e3ec1a6af9..d094e9129223 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -319,6 +319,7 @@
 
 #define MI_MODE         0x0209c
 # define VS_TIMER_DISPATCH                              (1 << 6)
+# define MI_FLUSH_ENABLE                                (1 << 11)
 
 #define SCPD0           0x0209c /* 915+ only */
 #define IER             0x020a0
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 51e9c9e718c4..cb3508f78bc3 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -220,9 +220,13 @@ static int init_render_ring(struct drm_device *dev,
 {
         drm_i915_private_t *dev_priv = dev->dev_private;
         int ret = init_ring_common(dev, ring);
+        int mode;
+
         if (IS_I9XX(dev) && !IS_GEN3(dev)) {
-                I915_WRITE(MI_MODE,
-                                (VS_TIMER_DISPATCH) << 16 | VS_TIMER_DISPATCH);
+                mode = VS_TIMER_DISPATCH << 16 | VS_TIMER_DISPATCH;
+                if (IS_GEN6(dev))
+                        mode |= MI_FLUSH_ENABLE << 16 | MI_FLUSH_ENABLE;
+                I915_WRITE(MI_MODE, mode);
         }
         return ret;
 }