From 22495b68f954c9018fd52bc620292cc80df2e418 Mon Sep 17 00:00:00 2001 From: Chris Wilson <chris@chris-wilson.co.uk> Date: Fri, 14 Sep 2018 09:00:16 +0100 Subject: [PATCH] drm/i915: Flush the tasklet when checking for idle 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> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20180914080017.30308-2-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/intel_engine_cs.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c index 10cd051ba29ee..217ed3ee1cab4 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; } -- GitLab