drm/i915: Re-instate request->uniq because it is extremely useful

The seqno value cannot always be used when debugging issues via trace
points. This is because it can be reset back to start, especially
during TDR type tests. Also, when the scheduler arrives the seqno is
only valid while a given request is executing on the hardware. While
the request is simply queued waiting for submission, it's seqno value
will be zero (meaning invalid).

v4: Wrapped a long line to keep the style checker happy.

v5: Added uniq to the dispatch trace point [Svetlana Kukanova]

For: VIZ-5115
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Tomas Elf <tomas.elf@intel.com>

3 files changed, 30 insertions, 11 deletions

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index f9785396e350..7492ce7caafd 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2012,6 +2012,8 @@ struct drm_i915_private {
 
 	struct intel_encoder *dig_port_map[I915_MAX_PORTS];
 
+	uint32_t request_uniq;
+
 	/*
 	 * NOTE: This is the dri1/ums dungeon, don't add stuff here. Your patch
 	 * will be rejected. Instead look for a better place.
@@ -2287,6 +2289,9 @@ struct drm_i915_gem_request {
 	  */
 	u32 seqno;
 
+	/* Unique identifier which can be used for trace points & debug */
+	uint32_t uniq;
+
 	/** Position in the ringbuffer of the start of the request */
 	u32 head;
 
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 71d9c247df22..724cfebb9918 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3008,7 +3008,8 @@ static void i915_gem_request_fence_value_str(struct fence *req_fence,
 
 	req = container_of(req_fence, typeof(*req), fence);
 
-	snprintf(str, size, "%d [%d]", req->fence.seqno, req->seqno);
+	snprintf(str, size, "%d [%d:%d]", req->fence.seqno, req->uniq,
+		 req->seqno);
 }
 
 static const struct fence_ops i915_gem_request_fops = {
@@ -3085,6 +3086,7 @@ __i915_gem_request_alloc(struct intel_engine_cs *engine,
 
 	req->i915 = dev_priv;
 	req->engine = engine;
+	req->uniq = dev_priv->request_uniq++;
 	req->ctx  = ctx;
 	i915_gem_context_reference(req->ctx);
 
diff --git a/drivers/gpu/drm/i915/i915_trace.h b/drivers/gpu/drm/i915/i915_trace.h
index b7c703146946..59a6266b2e53 100644
--- a/drivers/gpu/drm/i915/i915_trace.h
+++ b/drivers/gpu/drm/i915/i915_trace.h
@@ -458,6 +458,7 @@ TRACE_EVENT(i915_gem_ring_sync_to,
 			     __field(u32, dev)
 			     __field(u32, sync_from)
 			     __field(u32, sync_to)
+			     __field(u32, uniq_to)
 			     __field(u32, seqno)
 			     ),
 
@@ -465,13 +466,14 @@ TRACE_EVENT(i915_gem_ring_sync_to,
 			   __entry->dev = from->dev->primary->index;
 			   __entry->sync_from = from->id;
 			   __entry->sync_to = to_req->engine->id;
+			   __entry->uniq_to = to_req->uniq;
 			   __entry->seqno = i915_gem_request_get_seqno(req);
 			   ),
 
-	    TP_printk("dev=%u, sync-from=%u, sync-to=%u, seqno=%u",
+	    TP_printk("dev=%u, sync-from=%u, sync-to=%u, seqno=%u, to_uniq=%u",
 		      __entry->dev,
 		      __entry->sync_from, __entry->sync_to,
-		      __entry->seqno)
+		      __entry->seqno, __entry->uniq_to)
 );
 
 TRACE_EVENT(i915_gem_ring_dispatch,
@@ -481,6 +483,7 @@ TRACE_EVENT(i915_gem_ring_dispatch,
 	    TP_STRUCT__entry(
 			     __field(u32, dev)
 			     __field(u32, ring)
+			     __field(u32, uniq)
 			     __field(u32, seqno)
 			     __field(u32, flags)
 			     ),
@@ -490,13 +493,15 @@ TRACE_EVENT(i915_gem_ring_dispatch,
 						i915_gem_request_get_engine(req);
 			   __entry->dev = engine->dev->primary->index;
 			   __entry->ring = engine->id;
+			   __entry->uniq = req->uniq;
 			   __entry->seqno = i915_gem_request_get_seqno(req);
 			   __entry->flags = flags;
 			   i915_trace_irq_get(engine, req);
 			   ),
 
-	    TP_printk("dev=%u, ring=%u, seqno=%u, flags=%x",
-		      __entry->dev, __entry->ring, __entry->seqno, __entry->flags)
+	    TP_printk("dev=%u, ring=%u, uniq=%u, seqno=%u, flags=%x",
+		      __entry->dev, __entry->ring, __entry->uniq,
+		      __entry->seqno, __entry->flags)
 );
 
 TRACE_EVENT(i915_gem_ring_flush,
@@ -506,6 +511,7 @@ TRACE_EVENT(i915_gem_ring_flush,
 	    TP_STRUCT__entry(
 			     __field(u32, dev)
 			     __field(u32, ring)
+			     __field(u32, uniq)
 			     __field(u32, invalidate)
 			     __field(u32, flush)
 			     ),
@@ -513,12 +519,13 @@ TRACE_EVENT(i915_gem_ring_flush,
 	    TP_fast_assign(
 			   __entry->dev = req->engine->dev->primary->index;
 			   __entry->ring = req->engine->id;
+			   __entry->uniq = req->uniq;
 			   __entry->invalidate = invalidate;
 			   __entry->flush = flush;
 			   ),
 
-	    TP_printk("dev=%u, ring=%x, invalidate=%04x, flush=%04x",
-		      __entry->dev, __entry->ring,
+	    TP_printk("dev=%u, ring=%x, request=%u, invalidate=%04x, flush=%04x",
+		      __entry->dev, __entry->ring, __entry->uniq,
 		      __entry->invalidate, __entry->flush)
 );
 
@@ -529,6 +536,7 @@ DECLARE_EVENT_CLASS(i915_gem_request,
 	    TP_STRUCT__entry(
 			     __field(u32, dev)
 			     __field(u32, ring)
+			     __field(u32, uniq)
 			     __field(u32, seqno)
 			     ),
 
@@ -537,11 +545,13 @@ DECLARE_EVENT_CLASS(i915_gem_request,
 						i915_gem_request_get_engine(req);
 			   __entry->dev = engine->dev->primary->index;
 			   __entry->ring = engine->id;
+			   __entry->uniq = req ? req->uniq : 0;
 			   __entry->seqno = i915_gem_request_get_seqno(req);
 			   ),
 
-	    TP_printk("dev=%u, ring=%u, seqno=%u",
-		      __entry->dev, __entry->ring, __entry->seqno)
+	    TP_printk("dev=%u, ring=%u, uniq=%u, seqno=%u",
+		      __entry->dev, __entry->ring, __entry->uniq,
+		      __entry->seqno)
 );
 
 DEFINE_EVENT(i915_gem_request, i915_gem_request_add,
@@ -590,6 +600,7 @@ TRACE_EVENT(i915_gem_request_wait_begin,
 	    TP_STRUCT__entry(
 			     __field(u32, dev)
 			     __field(u32, ring)
+			     __field(u32, uniq)
 			     __field(u32, seqno)
 			     __field(bool, blocking)
 			     ),
@@ -605,13 +616,14 @@ TRACE_EVENT(i915_gem_request_wait_begin,
 						i915_gem_request_get_engine(req);
 			   __entry->dev = engine->dev->primary->index;
 			   __entry->ring = engine->id;
+			   __entry->uniq = req ? req->uniq : 0;
 			   __entry->seqno = i915_gem_request_get_seqno(req);
 			   __entry->blocking =
 				     mutex_is_locked(&engine->dev->struct_mutex);
 			   ),
 
-	    TP_printk("dev=%u, ring=%u, seqno=%u, blocking=%s",
-		      __entry->dev, __entry->ring,
+	    TP_printk("dev=%u, ring=%u, uniq=%u, seqno=%u, blocking=%s",
+		      __entry->dev, __entry->ring, __entry->uniq,
 		      __entry->seqno, __entry->blocking ?  "yes (NB)" : "no")
 );