drm/i915: Keep a global seqno per-engine

Replace the global device seqno with one for each engine, and account
for in-flight seqno on each separately. This is consistent with
dma-fence as each timeline has separate fence-contexts for each engine
and a seqno is only ordered within a fence-context (i.e.  seqno do not
need to be ordered wrt to other engines, just ordered within a single
engine). This is required to enable request rewinding for preemption on
individual engines (we have to rewind the global seqno to avoid
overflow, and we do not have to rewind all engines just to preempt one.)

v2: Rename active_seqno to inflight_seqnos to more clearly indicate that
it is a counter and not equivalent to the existing seqno. Update
functions that operated on active_seqno similarly.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170223074422.4125-3-chris@chris-wilson.co.uk

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 4091c97be6ec..b91c2c7ef5a6 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -556,7 +556,7 @@ static inline u32 intel_engine_last_submit(struct intel_engine_cs *engine)
 	 * wtih serialising this hint with anything, so document it as
 	 * a hint and nothing more.
 	 */
-	return READ_ONCE(engine->timeline->last_submitted_seqno);
+	return READ_ONCE(engine->timeline->seqno);
 }
 
 int init_workarounds_ring(struct intel_engine_cs *engine);
@@ -630,7 +630,7 @@ static inline bool intel_engine_wakeup(const struct intel_engine_cs *engine)
 
 void intel_engine_reset_breadcrumbs(struct intel_engine_cs *engine);
 void intel_engine_fini_breadcrumbs(struct intel_engine_cs *engine);
-unsigned int intel_breadcrumbs_busy(struct drm_i915_private *i915);
+bool intel_breadcrumbs_busy(struct intel_engine_cs *engine);
 
 static inline u32 *gen8_emit_pipe_control(u32 *batch, u32 flags, u32 offset)
 {