drm/i915/gt: Add some debug tracing for context pinning

Add the context pin/unpin events to the trace for post-mortem debugging.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190625194859.28005-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/gt/intel_context.c

@@ -59,6 +59,10 @@ int __intel_context_do_pin(struct intel_context *ce)
 		if (err)
 			goto err;
 
+		GEM_TRACE("%s context:%llx pin ring:{head:%04x, tail:%04x}\n",
+			  ce->engine->name, ce->ring->timeline->fence_context,
+			  ce->ring->head, ce->ring->tail);
+
 		i915_gem_context_get(ce->gem_context); /* for ctx->ppgtt */
 
 		smp_mb__before_atomic(); /* flush pin before it is visible */
@@ -85,6 +89,9 @@ void intel_context_unpin(struct intel_context *ce)
 	mutex_lock_nested(&ce->pin_mutex, SINGLE_DEPTH_NESTING);
 
 	if (likely(atomic_dec_and_test(&ce->pin_count))) {
+		GEM_TRACE("%s context:%llx retire\n",
+			  ce->engine->name, ce->ring->timeline->fence_context);
+
 		ce->ops->unpin(ce);
 
 		i915_gem_context_put(ce->gem_context);
@@ -127,6 +134,9 @@ static void __intel_context_retire(struct i915_active *active)
 {
 	struct intel_context *ce = container_of(active, typeof(*ce), active);
 
+	GEM_TRACE("%s context:%llx retire\n",
+		  ce->engine->name, ce->ring->timeline->fence_context);
+
 	if (ce->state)
 		__context_unpin_state(ce->state);
 

drivers/gpu/drm/i915/gt/intel_ringbuffer.c

@@ -1197,6 +1197,7 @@ int intel_ring_pin(struct intel_ring *ring)
 	GEM_BUG_ON(ring->vaddr);
 	ring->vaddr = addr;
 
+	GEM_TRACE("ring:%llx pin\n", ring->timeline->fence_context);
 	return 0;
 
 err_ring:
@@ -1223,6 +1224,8 @@ void intel_ring_unpin(struct intel_ring *ring)
 	if (!atomic_dec_and_test(&ring->pin_count))
 		return;
 
+	GEM_TRACE("ring:%llx unpin\n", ring->timeline->fence_context);
+
 	/* Discard any unused bytes beyond that submitted to hw. */
 	intel_ring_reset(ring, ring->tail);