drm/i915/perf: rate limit spurious oa report notice

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 known 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.

v2: (Chris) avoid inconsistent warning on throttle with
    printk_ratelimit()
v3: (Matt) init and summarise with stream init/close not driver init/fini

Signed-off-by: Robert Bragg <robert@sixbynine.org>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170511154345.962-9-lionel.g.landwerlin@intel.com
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 22b2ea3ea66f..66dee15e4fc0 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2354,6 +2354,12 @@ struct drm_i915_private {
 			wait_queue_head_t poll_wq;
 			bool pollin;
 
+			/**
+			 * For rate limiting any notifications of spurious
+			 * invalid OA reports
+			 */
+			struct ratelimit_state spurious_report_rs;
+
 			bool periodic;
 			int period_exponent;