diff mbox series

drm/i915: Flush the tasklet when checking for idle

Message ID 20180913080536.31150-1-chris@chris-wilson.co.uk (mailing list archive)
State New, archived
Headers show
Series drm/i915: Flush the tasklet when checking for idle | expand

Commit Message

Chris Wilson Sept. 13, 2018, 8:05 a.m. UTC
In order to reduce latency when checking for idle we kick the tasklet
directly. Sometimes this is not enough as it is queued on another cpu
and so to improve the accuracy of this idle-check (and so to reduce
latency overall by avoiding another pass, or worse declaring a timeout!)
wait for the tasklet to complete.

References: https://bugs.freedesktop.org/show_bug.cgi?id=107916
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Michel Thierry <michel.thierry@intel.com>
---
 drivers/gpu/drm/i915/intel_engine_cs.c | 3 +++
 1 file changed, 3 insertions(+)
diff mbox series

Patch

diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
index 10cd051ba29e..217ed3ee1cab 100644
--- a/drivers/gpu/drm/i915/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/intel_engine_cs.c
@@ -990,6 +990,9 @@  bool intel_engine_is_idle(struct intel_engine_cs *engine)
 		}
 		local_bh_enable();
 
+		/* Otherwise flush the tasklet if it was on another cpu */
+		tasklet_unlock_wait(t);
+
 		if (READ_ONCE(engine->execlists.active))
 			return false;
 	}