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

John Harrison
2022-01-19T01:39:08Z

On 1/18/2022 13:43, Matthew Brost wrote:
> Now that the error capture is fully decoupled from fence signalling
> (request retirement to free memory, which is turn depends on resets) we
s/is/in/

With that fixed:
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>

John.

> can safely flush the G2H handler during a GT reset. This is eliminates
> corner cases where GuC generated G2H (e.g. engine resets) race with a GT
> reset.
>
> Signed-off-by: Matthew Brost <mattthew.brost@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 cdd8d691251ff..1a11e8986948b 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);
> }