Re: [Intel-gfx] [PATCH v2 1/3] drm/i915/guc: Flush context destruction worker at suspend

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Mon, Aug 14, 2023 at 06:12:08PM -0700, Alan Previn wrote:
> When suspending, flush the context-guc-id
> deregistration worker at the final stages of
> intel_gt_suspend_late when we finally call gt_sanitize
> that eventually leads down to __uc_sanitize so that
> the deregistration worker doesn't fire off later as
> we reset the GuC microcontroller.
> 
> Signed-off-by: Alan Previn <alan.previn.teres.alexis@intel.com>
> ---
>  drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c | 5 +++++
>  drivers/gpu/drm/i915/gt/uc/intel_guc_submission.h | 2 ++
>  drivers/gpu/drm/i915/gt/uc/intel_uc.c             | 2 ++
>  3 files changed, 9 insertions(+)
> 
> 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 a0e3ef1c65d2..050572bb8dbe 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> @@ -1578,6 +1578,11 @@ static void guc_flush_submissions(struct intel_guc *guc)
>  	spin_unlock_irqrestore(&sched_engine->lock, flags);
>  }
>  
> +void intel_guc_submission_flush_work(struct intel_guc *guc)
> +{
> +	flush_work(&guc->submission_state.destroyed_worker);
> +}
> +
>  static void guc_flush_destroyed_contexts(struct intel_guc *guc);
>  
>  void intel_guc_submission_reset_prepare(struct intel_guc *guc)
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.h b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.h
> index c57b29cdb1a6..b6df75622d3b 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.h
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.h
> @@ -38,6 +38,8 @@ int intel_guc_wait_for_pending_msg(struct intel_guc *guc,
>  				   bool interruptible,
>  				   long timeout);
>  
> +void intel_guc_submission_flush_work(struct intel_guc *guc);
> +
>  static inline bool intel_guc_submission_is_supported(struct intel_guc *guc)
>  {
>  	return guc->submission_supported;
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_uc.c b/drivers/gpu/drm/i915/gt/uc/intel_uc.c
> index 98b103375b7a..eb3554cb5ea4 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_uc.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_uc.c
> @@ -693,6 +693,8 @@ void intel_uc_suspend(struct intel_uc *uc)
>  		return;
>  	}
>  
> +	intel_guc_submission_flush_work(guc);
> +

what happens if a new job comes exactly here?
This still sounds a bit racy, although this already looks
much cleaner than the previous version.

>  	with_intel_runtime_pm(&uc_to_gt(uc)->i915->runtime_pm, wakeref) {
>  		err = intel_guc_suspend(guc);
>  		if (err)
> -- 
> 2.39.0
>