[Intel-gfx] [PATCH 3/3] drm/i915/perf: rate limit spurious oa report notice

[Robert Bragg]

This change is pre-emptively aiming to avoid a potential cause of kernel
logging noise in case some condition were to result in us seeing invalid
OA reports.

The workaround for the OA unit's tail pointer race condition is what
avoids the primary know cause of invalid reports being seen and with
that in place we aren't expecting to see this notice but it can't be
entirely ruled out.

Just in case some condition does lead to the notice then it's likely
that it will be triggered repeatedly while attempting to append a
sequence of reports and depending on the configured OA sampling
frequency that might be a large number of repeat notices.

Signed-off-by: Robert Bragg <robert at sixbynine.org>
---
 drivers/gpu/drm/i915/i915_perf.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c
index d04ebaa8406e..a901bcd80263 100644
--- a/drivers/gpu/drm/i915/i915_perf.c
+++ b/drivers/gpu/drm/i915/i915_perf.c
@@ -632,7 +632,8 @@ static int gen7_append_oa_reports(struct i915_perf_stream *stream,
 		 * copying it to userspace...
 		 */
 		if (report32[0] == 0) {
-			DRM_NOTE("Skipping spurious, invalid OA report\n");
+			if (printk_ratelimit())
+				DRM_NOTE("Skipping spurious, invalid OA report\n");
 			continue;
 		}
 
-- 
2.11.1