-----Original Message-----
From: Intel-xe <intel-xe-bounces@lists.freedesktop.org> On Behalf Of Nirmoy Das
Sent: Monday, October 21, 2024 2:12 PM
To: intel-xe@lists.freedesktop.org
Cc: Das, Nirmoy <nirmoy.das@intel.com>; Ghimiray, Himal Prasad <himal.prasad.ghimiray@intel.com>; Auld, Matthew <matthew.auld@intel.com>; Brost, Matthew <matthew.brost@intel.com>; Upadhyay, Tejas <tejas.upadhyay@intel.com>
Subject: [PATCH] drm/xe: Don't restart parallel queues multiple times on GT reset

In case of parallel submissions multiple GuC id will point to the
same exec queue and on GT reset such exec queues will get restarted
multiple times which is not desirable.

Link: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/2295
Cc: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Tejas Upadhyay <tejas.upadhyay@intel.com>
Signed-off-by: Nirmoy Das <nirmoy.das@intel.com>

This makes sense, though I'd assume we'd want at least one of
the GuC IDs to restart the exec queue during a GT reset.  Is that
what exec_queue_enabled helps allow?

Yes exec_queue_enabled() should be false for the 1st one but as Matt pointed out this is racy. So I will resend this with

Matt suggested check.

Regards,

Nirmoy

I won't block on it presently, just was curious if that case was being
handled, or if we didn't need to worry about it.

Reviewed-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
-Jonathan Cavitt

---
 drivers/gpu/drm/xe/xe_guc_submit.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/xe/xe_guc_submit.c b/drivers/gpu/drm/xe/xe_guc_submit.c
index 0b81972ff651..6aeb007eaf06 100644
--- a/drivers/gpu/drm/xe/xe_guc_submit.c
+++ b/drivers/gpu/drm/xe/xe_guc_submit.c
@@ -1784,8 +1784,13 @@ int xe_guc_submit_start(struct xe_guc *guc)
 
 	mutex_lock(&guc->submission_state.lock);
 	atomic_dec(&guc->submission_state.stopped);
-	xa_for_each(&guc->submission_state.exec_queue_lookup, index, q)
+	xa_for_each(&guc->submission_state.exec_queue_lookup, index, q) {
+		/* Skip restarting parallel queues */
+		if (exec_queue_enabled(q) && xe_exec_queue_is_parallel(q))
+			continue;
+
 		guc_exec_queue_start(q);
+	}
 	mutex_unlock(&guc->submission_state.lock);
 
 	wake_up_all(&guc->ct.wq);
-- 
2.46.0