[PATCH 3/9] intel_gpu_top: ignore out of range ring pointers

[Robert Bragg <robert.bragg@intel.com>]

---
 tools/intel_gpu_top.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/tools/intel_gpu_top.c b/tools/intel_gpu_top.c
index f60e58b..7574ef0 100644
--- a/tools/intel_gpu_top.c
+++ b/tools/intel_gpu_top.c
@@ -344,6 +344,15 @@ static void ring_sample(struct ring *ring)
 	ring->head = ring_read(ring, RING_HEAD) & HEAD_ADDR;
 	ring->tail = ring_read(ring, RING_TAIL) & TAIL_ADDR;
 
+	/* We sometimes read spurious, out of range pointers which
+	 * we want to ignore. We treat them as idle for now... */
+	if (ring->head > ring->size || ring->tail > ring->size)
+	{
+	    fprintf(stderr, "Ignoring spurious ring pointer\n");
+	    ring->idle++;
+	    return;
+	}
+
 	if (ring->tail == ring->head)
 		ring->idle++;
 
-- 
2.0.1

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