drm/i915: wait for rings to become idle once disabled

make sure we wait for rings to become idle once they are
disabled. In case of timeout print an error message

Signed-off-by: Naresh Kumar Kachhi <naresh.kumar.kachhi@intel.com>
[danvet: Frob patch as suggested by Chris.]
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 42b400144379..617634b6a6c2 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -444,6 +444,8 @@ static int init_ring_common(struct intel_ring_buffer *ring)
         I915_WRITE_CTL(ring, 0);
         I915_WRITE_HEAD(ring, 0);
         ring->write_tail(ring, 0);
+        if (wait_for_atomic((I915_READ_MODE(ring) & MODE_IDLE) != 0, 1000))
+                DRM_ERROR("%s :timed out trying to stop ring\n", ring->name);
 
         if (I915_NEED_GFX_HWS(dev))
                 intel_ring_setup_status_page(ring);