drm/1915: ringbuffer wait for idle function

Added a new function which waits for the ringbuffer space to be equal to
(total - 8). This is the empty condition of the ringbuffer, and
equivalent to head==tail.

Also modified two users of this functionality elsewhere in the code.

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index f23cc5f037a6..16cb125eb117 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -164,7 +164,13 @@ intel_read_status_page(struct intel_ring_buffer *ring,
 #define I915_BREADCRUMB_INDEX           0x21
 
 void intel_cleanup_ring_buffer(struct intel_ring_buffer *ring);
+
 int __must_check intel_wait_ring_buffer(struct intel_ring_buffer *ring, int n);
+static inline int intel_wait_ring_idle(struct intel_ring_buffer *ring)
+{
+        return intel_wait_ring_buffer(ring, ring->space - 8);
+}
+
 int __must_check intel_ring_begin(struct intel_ring_buffer *ring, int n);
 
 static inline void intel_ring_emit(struct intel_ring_buffer *ring,