[PATCH 3/3] drm/i915/guc: Flush G2H handler during a GT reset

[Matthew Brost]

On Thu, Jan 20, 2022 at 05:36:22PM -0800, John Harrison wrote:
> On 1/19/2022 13:24, Matthew Brost wrote:
> > Now that the error capture is fully decoupled from fence signalling
> > (request retirement to free memory, which in turn depends on resets) we
> > can safely flush the G2H handler during a GT reset. This is eliminates
> This eliminates
> 
> John.
> 

Yep, will fixup in the next rev.

Matt

> > corner cases where GuC generated G2H (e.g. engine resets) race with a GT
> > reset.
> > 
> > v2:
> >   (John Harrison)
> >    - Fix typo in commit message (s/is/in)
> > 
> > Signed-off-by: Matthew Brost <matthew.brost at intel.com>
> > Reviewed-by: John Harrison <John.C.Harrison at Intel.com>
> > ---
> >   .../gpu/drm/i915/gt/uc/intel_guc_submission.c  | 18 +-----------------
> >   1 file changed, 1 insertion(+), 17 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 514b3060b141..406dd2e3f5a9 100644
> > --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> > +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> > @@ -1396,8 +1396,6 @@ static void guc_flush_destroyed_contexts(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;
> > @@ -1414,21 +1412,7 @@ void intel_guc_submission_reset_prepare(struct intel_guc *guc)
> >   	guc_flush_submissions(guc);
> >   	guc_flush_destroyed_contexts(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);
> >   	scrub_guc_desc_for_outstanding_g2h(guc);
> >   }
>