drm/i915: Include fence-hint for timeout warning

If an asynchronous wait on a foriegn fence, we print a warning
indicating which fence was not signaled. As i915_sw_fences become more
common, include the debug hint (the symbol-name of the target) to help
identify the waiter. E.g.

[   31.968144] Asynchronous wait on fence sw_sync:gem_eio:1 timed out (hint:submit_notify [i915])

We also want to downgrade from a warning to a notice (normal but
significant condition) as the timeout is imposed and controlled by the
caller (i.e. it is deliberate) and can be provoked by userspace.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180914124007.18790-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_sw_fence.c

@@ -24,13 +24,13 @@ enum {
 	DEBUG_FENCE_NOTIFY,
 };
 
-#ifdef CONFIG_DRM_I915_SW_FENCE_DEBUG_OBJECTS
-
 static void *i915_sw_fence_debug_hint(void *addr)
 {
 	return (void *)(((struct i915_sw_fence *)addr)->flags & I915_SW_FENCE_MASK);
 }
 
+#ifdef CONFIG_DRM_I915_SW_FENCE_DEBUG_OBJECTS
+
 static struct debug_obj_descr i915_sw_fence_debug_descr = {
 	.name = "i915_sw_fence",
 	.debug_hint = i915_sw_fence_debug_hint,
@@ -393,10 +393,11 @@ static void timer_i915_sw_fence_wake(struct timer_list *t)
 	if (!fence)
 		return;
 
-	pr_warn("asynchronous wait on fence %s:%s:%x timed out\n",
-		cb->dma->ops->get_driver_name(cb->dma),
-		cb->dma->ops->get_timeline_name(cb->dma),
-		cb->dma->seqno);
+	pr_notice("Asynchronous wait on fence %s:%s:%x timed out (hint:%pS)\n",
+		  cb->dma->ops->get_driver_name(cb->dma),
+		  cb->dma->ops->get_timeline_name(cb->dma),
+		  cb->dma->seqno,
+		  i915_sw_fence_debug_hint(fence));
 
 	i915_sw_fence_complete(fence);
 }