Quoting Chris Wilson (2020-04-23 07:29:05) > intel_gt_wait_for_idle() tries to wait until all the outstanding requests > are retired and the GPU is idle. As a side effect of retiring requests, > we may submit more work to flush any pm barriers, and so the > wait-for-idle tries to flush the background pm work and catch the new > requests. However, if the work completed in the background before we > were able to flush, it would queue the extra barrier request without us > noticing -- and so we would return from wait-for-idle with one request > remaining. (This breaks e.g. record_default_state where we need to wait > until that barrier is retired, and it may slow suspend down by causing > us to wait on the background retirement worker as opposed to immediately > retiring the barrier.) > > However, since we track if there has been a submission since the engine > pm barrier, we can very quickly detect if the idle barrier is still > outstanding. > > Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/1763 > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > Cc: Matthew Auld <matthew.auld@xxxxxxxxx> > Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> > --- > drivers/gpu/drm/i915/gt/intel_gt_requests.c | 14 ++++++++++++-- > 1 file changed, 12 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/i915/gt/intel_gt_requests.c b/drivers/gpu/drm/i915/gt/intel_gt_requests.c > index dec96a731a77..1781f176886a 100644 > --- a/drivers/gpu/drm/i915/gt/intel_gt_requests.c > +++ b/drivers/gpu/drm/i915/gt/intel_gt_requests.c > @@ -26,6 +26,11 @@ static bool retire_requests(struct intel_timeline *tl) > return !i915_active_fence_isset(&tl->last_request); > } > > +static bool engine_active(const struct intel_engine_cs *engine) > +{ > + return READ_ONCE(engine->wakeref_serial) != READ_ONCE(engine->serial); This will be false when we have submitted but not yet retired. I was better with checking the timeline. -Chris _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
