Re: [PATCH 6/6] drm/xe: Clean up GuC software state after a wedge

["Summers, Stuart" <stuart.summers@intel.com>]

On Tue, 2025-10-14 at 18:09 +0000, Stuart Summers wrote:
> Comments also added to the code, but in the event of
> a wedge or a hardware failure while communication with
> GuC is outstanding (e.g. during a schedule disable or
> context deregistration), the driver doesn't automatically
> reset the software state as it would in a typical GT reset
> since we are trying to save the state for debug. However
> once the user unbinds the driver we still need to go through
> and clean everything up for these exec queues so we don't
> leak memory on the DRM side (e.g. LRC or LRC BO).
> 
> Add a kick start to the DRM scheduler to handle any outstanding
> messages on hold during the wedge and go through the GuC stop
> flow to simulate that reset on teardown.
> 
> Signed-off-by: Stuart Summers <stuart.summers@intel.com>

Please hold on review here. I think there's still something missing on
the wedge cleanup case that causes issues after wedging and then doing
binds/unbinds in a loop after. I'm working to resolve that and I'll
post a new series after.

Thanks,
Stuart

> ---
>  drivers/gpu/drm/xe/xe_guc_submit.c | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
> 
> diff --git a/drivers/gpu/drm/xe/xe_guc_submit.c
> b/drivers/gpu/drm/xe/xe_guc_submit.c
> index 5ec1e4a83d68..0bbae336c722 100644
> --- a/drivers/gpu/drm/xe/xe_guc_submit.c
> +++ b/drivers/gpu/drm/xe/xe_guc_submit.c
> @@ -276,6 +276,14 @@ static void guc_submit_fini(struct drm_device
> *drm, void *arg)
>         struct xe_gt *gt = guc_to_gt(guc);
>         int ret;
>  
> +       /*
> +        * If GuC stopped responding during deregistration
> +        * some queues can be left in a bad state. Ensure
> +        * these are all cleaned up by going through the
> +        * GuC software reset flow.
> +        */
> +       xe_guc_stop(guc);
> +
>         ret = wait_event_timeout(guc->submission_state.fini_wq,
>                                  xa_empty(&guc-
> >submission_state.exec_queue_lookup),
>                                  HZ * 5);
> @@ -295,6 +303,13 @@ static void guc_submit_wedged_fini(void *arg)
>  
>         mutex_lock(&guc->submission_state.lock);
>         xa_for_each(&guc->submission_state.exec_queue_lookup, index,
> q) {
> +               /*
> +                * Kick start the scheduler since some messages
> +                * might have been added while the scheduler was
> +                * stopped during a wedge event.
> +                */
> +               xe_sched_submission_start(&q->guc->sched);
> +
>                 if (exec_queue_wedged(q)) {
>                         mutex_unlock(&guc->submission_state.lock);
>                         xe_exec_queue_put(q);