On Fri, Aug 20, 2021 at 05:25:41PM -0700, Daniele Ceraolo Spurio wrote:
>
>
> On 8/18/2021 11:16 PM, Matthew Brost wrote:
> > It isn't safe to scrub for missing G2H or continue with the reset until
> > all G2H processing is complete. Flush the G2H work queue during reset to
> > ensure it is done running.
>
> Might be worth moving this patch closer to "drm/i915/guc: Process all G2H
> message at once in work queue".
>
Sure.
> > Fixes: eb5e7da736f3 ("drm/i915/guc: Reset implementation for new GuC interface")
> > Signed-off-by: Matthew Brost <matthew.brost@xxxxxxxxx>
> > ---
> > .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 18 ++----------------
> > 1 file changed, 2 insertions(+), 16 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> > index 4cf5a565f08e..9a53bae367b1 100644
> > --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> > +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> > @@ -714,8 +714,6 @@ static void guc_flush_submissions(struct intel_guc *guc)
> > void intel_guc_submission_reset_prepare(struct intel_guc *guc)
> > {
> > - int i;
> > -
> > if (unlikely(!guc_submission_initialized(guc))) {
> > /* Reset called during driver load? GuC not yet initialised! */
> > return;
> > @@ -731,20 +729,8 @@ void intel_guc_submission_reset_prepare(struct intel_guc *guc)
> > guc_flush_submissions(guc);
> > - /*
> > - * Handle any outstanding G2Hs before reset. Call IRQ handler directly
> > - * each pass as interrupt have been disabled. We always scrub for
> > - * outstanding G2H as it is possible for outstanding_submission_g2h to
> > - * be incremented after the context state update.
> > - */
> > - for (i = 0; i < 4 && atomic_read(&guc->outstanding_submission_g2h); ++i) {
> > - intel_guc_to_host_event_handler(guc);
> > -#define wait_for_reset(guc, wait_var) \
> > - intel_guc_wait_for_pending_msg(guc, wait_var, false, (HZ / 20))
> > - do {
> > - wait_for_reset(guc, &guc->outstanding_submission_g2h);
> > - } while (!list_empty(&guc->ct.requests.incoming));
> > - }
> > + flush_work(&guc->ct.requests.worker);
> > +
>
> We're now not waiting in the requests anymore, just ensuring that the
> processing of the ones we already received is done. Is this intended? We do
> still handle the remaining oustanding submission in the scrub so it's
> functionally correct, but the commit message doesn't state the change in
> waiting behavior, so wanted to double check it was planned.
>
Yes, it is planned as scrub code should be able to cope with any missing
G2H. Will update the commit message to reflect that.
Matt
> Daniele
>
> > scrub_guc_desc_for_outstanding_g2h(guc);
> > }
>
