drm/i915: Dumb down the semaphore logic

While I think the previous code is correct, it was hard to follow and
hard to debug. Since we already have a ring abstraction, might as well
use it to handle the semaphore updates and compares.

I don't expect this code to make semaphores better or worse, but you
never know...

v2:
Remove magic per Keith's suggestions.
Ran Daniel's gem_ring_sync_loop test on this.

v3:
Ignored one of Keith's suggestions.

v4:
Removed some bloat per Daniel's recommendation.

Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Keith Packard <keithp@keithp.com>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 5 insertions, 3 deletions

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 600e67abd8d0..68281c96c558 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -75,7 +75,12 @@ struct  intel_ring_buffer {
         int             (*dispatch_execbuffer)(struct intel_ring_buffer *ring,
                                                u32 offset, u32 length);
         void            (*cleanup)(struct intel_ring_buffer *ring);
+        int             (*sync_to)(struct intel_ring_buffer *ring,
+                                   struct intel_ring_buffer *to,
+                                   u32 seqno);
 
+        u32             semaphore_register[3]; /*our mbox written by others */
+        u32             signal_mbox[2]; /* mboxes this ring signals to */
         /**
          * List of objects currently involved in rendering from the
          * ringbuffer.
@@ -180,9 +185,6 @@ static inline void intel_ring_emit(struct intel_ring_buffer *ring,
 void intel_ring_advance(struct intel_ring_buffer *ring);
 
 u32 intel_ring_get_seqno(struct intel_ring_buffer *ring);
-int intel_ring_sync(struct intel_ring_buffer *ring,
-                    struct intel_ring_buffer *to,
-                    u32 seqno);
 
 int intel_init_render_ring_buffer(struct drm_device *dev);
 int intel_init_bsd_ring_buffer(struct drm_device *dev);