[Intel-gfx] [PATCH 07/10] drm/i915: timeout parameter for seqno wait

[Ben Widawsky]

Insert a wait parameter in the code so we can possibly timeout on a
seqno wait if need be. The code should be functionally the same as
before because all the callers will continue to retry if an arbitrary
timeout elapses.

Signed-off-by: Ben Widawsky <benjamin.widawsky at intel.com>
---
 drivers/gpu/drm/i915/i915_gem.c |   41 ++++++++++++++++++++++++++++-----------
 1 file changed, 30 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 920dbc1..7bfad04 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1847,25 +1847,36 @@ i915_gem_retire_work_handler(struct work_struct *work)
 	mutex_unlock(&dev->struct_mutex);
 }
 
+#define SEQNO_WAIT_DEFAULT (3000000UL)
 static int __wait_seqno(struct intel_ring_buffer *ring, u32 seqno,
-			bool interruptible)
+			bool interruptible, long *usecs)
 {
 	drm_i915_private_t *dev_priv = ring->dev->dev_private;
-	int ret = 0;
+	const long timeout = usecs_to_jiffies(*usecs);
+	long end;
 
 #define EXIT_COND \
 	(i915_seqno_passed(ring->get_seqno(ring), seqno) || \
 	atomic_read(&dev_priv->mm.wedged))
 
 	if (interruptible)
-		ret = wait_event_interruptible(ring->irq_queue,
-					       EXIT_COND);
+		end = wait_event_interruptible_timeout(ring->irq_queue,
+						       EXIT_COND,
+						       timeout);
 	else
-		wait_event(ring->irq_queue, EXIT_COND);
-
+		end = wait_event_timeout(ring->irq_queue, EXIT_COND, timeout);
 #undef EXIT_COND
 
-	return ret;
+	switch (end) {
+	case 0: /* Tiemout */
+		return -ETIME;
+	case -ERESTARTSYS: /* Signal */
+		return -ERESTARTSYS;
+	default: /* Completed */
+		BUG_ON(end < 0); /* We're not aware of other errors */
+		*usecs = jiffies_to_usecs(timeout - end);
+		return 0;
+	}
 }
 
 /**
@@ -1916,7 +1927,12 @@ i915_wait_request(struct intel_ring_buffer *ring,
 		if (WARN_ON(!ring->irq_get(ring)))
 			return -EBUSY;
 
-		ret = __wait_seqno(ring, seqno, dev_priv->mm.interruptible);
+		do {
+			long time = SEQNO_WAIT_DEFAULT;
+			ret  = __wait_seqno(ring, seqno,
+					    dev_priv->mm.interruptible,
+					    &time);
+		} while (ret == -ETIME);
 
 		ring->irq_put(ring);
 		trace_i915_gem_request_wait_end(ring, seqno);
@@ -3012,13 +3028,16 @@ i915_gem_ring_throttle(struct drm_device *dev, struct drm_file *file)
 		 * lockless.
 		 */
 		if (ring->irq_get(ring)) {
-			ret = __wait_seqno(ring, seqno, true);
+			do {
+				long time = SEQNO_WAIT_DEFAULT;
+				ret = __wait_seqno(ring, seqno, true, &time);
+			} while (ret == -ETIME);
 			ring->irq_put(ring);
-
 			if (ret == 0 && atomic_read(&dev_priv->mm.wedged))
 				ret = -EIO;
-		} else
+		} else {
 			ret = -EBUSY;
+		}
 	}
 
 	if (ret == 0)
-- 
1.7.10