Re: [RFC PATCH 1/3] drm/xe: skip banning kernel migration queue on TDR timeout

[Matthew Auld <matthew.auld@intel.com>]

On 03/06/2026 13:06, Sanjay Yadav wrote:
> guc_exec_queue_timedout_job() unconditionally bans the queue once a
> job times out. For the kernel migration queue this is fatal — once
> banned, no page table migrations can complete and the GPU is
> effectively dead until driver reload.
> 
> The submission is already stopped and the timed-out job is erred out,
> so banning is not needed for correctness. GT reset handles the actual
> hardware recovery. Skip banning for kernel queues so they remain
> available after reset.

Is wedging/reload not the more correct thing here? Kernel job is usually 
performing critical and potentially security sensitive work, like memory 
clearing, migrations, binding etc. If something goes wrong in one of 
those jobs, how should we go about recovering from that? Is driver 
reload/wedge not the more appropriate thing here, or least would need a 
more elaborate recovery?

For example, memclear get nuked, what stops the user from accessing 
uncleared memory later? Or a migration/copy/save/restore/ job gets 
nuked, from correctness pov how do we recover from that?

> 
> Fixes: bb63e7257e63 ("drm/xe: Avoid toggling schedule state to check LRC timestamp in TDR")
> Cc: Matthew Brost <matthew.brost@intel.com>
> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Assisted-by: Claude:claude-opus-4.6
> Suggested-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
> Signed-off-by: Sanjay Yadav <sanjay.kumar.yadav@intel.com>
> ---
>   drivers/gpu/drm/xe/xe_guc_submit.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_guc_submit.c b/drivers/gpu/drm/xe/xe_guc_submit.c
> index ab501513d806..e6ad57cbbf0e 100644
> --- a/drivers/gpu/drm/xe/xe_guc_submit.c
> +++ b/drivers/gpu/drm/xe/xe_guc_submit.c
> @@ -1543,7 +1543,8 @@ guc_exec_queue_timedout_job(struct drm_sched_job *drm_job)
>   	if (!exec_queue_killed(q))
>   		wedged = guc_submit_hint_wedged(exec_queue_to_guc(q));
>   
> -	set_exec_queue_banned(q);
> +	if (!(q->flags & EXEC_QUEUE_FLAG_KERNEL))
> +		set_exec_queue_banned(q);
>   
>   	/* Kick job / queue off hardware */
>   	if (!wedged && (exec_queue_enabled(primary) ||