Merge branches 'x86-alternatives-for-linus', 'x86-fpu-for-linus', 'x86-hwmon-for...

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / gpu / drm / i915 / intel_ringbuffer.c

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 89a65be8a3f364359edaf6add71b6259affa3cbd..31cd7e33e8208b8112ed7cb2b278e8cc8b84fc61 100644 (file)
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -696,20 +696,17 @@ int intel_wait_ring_buffer(struct drm_device *dev,
        drm_i915_private_t *dev_priv = dev->dev_private;
        u32 head;
 
-       head = intel_read_status_page(ring, 4);
-       if (head) {
-               ring->head = head & HEAD_ADDR;
-               ring->space = ring->head - (ring->tail + 8);
-               if (ring->space < 0)
-                       ring->space += ring->size;
-               if (ring->space >= n)
-                       return 0;
-       }
-
        trace_i915_ring_wait_begin (dev);
        end = jiffies + 3 * HZ;
        do {
-               ring->head = I915_READ_HEAD(ring) & HEAD_ADDR;
+               /* If the reported head position has wrapped or hasn't advanced,
+                * fallback to the slow and accurate path.
+                */
+               head = intel_read_status_page(ring, 4);
+               if (head < ring->actual_head)
+                       head = I915_READ_HEAD(ring);
+               ring->actual_head = head;
+               ring->head = head & HEAD_ADDR;
                ring->space = ring->head - (ring->tail + 8);
                if (ring->space < 0)
                        ring->space += ring->size;