Re: [PATCH v4 2/2] drm/xe/guc: Preserve HW error state in wedged mode 2

[Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>]

On 6/29/2026 7:08 AM, Zhanjun Dong wrote:
> When HW reports an uncorrectable error, debugging the root cause may
> require halting the GPU in the error state so scan dumps can be collected
> and inspected.
>
> Use wedged_mode=2 for this debug mode. In this mode, Xe already avoids GPU
> reset on hangs, so also skip the engine reset cleanup path for GuC
> uncorrectable error reports to keep the HW state intact.
>
> Signed-off-by: Zhanjun Dong <zhanjun.dong@intel.com>
> ---
>   drivers/gpu/drm/xe/xe_guc_submit.c | 6 ++++--
>   1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/xe/xe_guc_submit.c b/drivers/gpu/drm/xe/xe_guc_submit.c
> index 29ccabc4b7a4..05fa4e466461 100644
> --- a/drivers/gpu/drm/xe/xe_guc_submit.c
> +++ b/drivers/gpu/drm/xe/xe_guc_submit.c
> @@ -3024,8 +3024,10 @@ int xe_guc_uncorrectable_error_handler(struct xe_guc *guc, u32 *msg, u32 len)
>   
>   	trace_xe_guc_uncorrectable_error(q);
>   
> -	/* Treat the same as engine reset */
> -	xe_guc_exec_queue_reset_trigger_cleanup(q);
> +	if (guc_to_xe(guc)->wedged.mode != XE_WEDGED_MODE_UPON_ANY_HANG_NO_RESET) {
> +		/* Treat the same as engine reset */
> +		xe_guc_exec_queue_reset_trigger_cleanup(q);
> +	}

This doesn't seem the correct place to do this. On one side, if we skip 
the reset call here, if the queue it's actually hung on the engine then 
the fence will eventually timeout and guc_exec_queue_timedout_job() will 
be called anyway. On the other side, 
XE_WEDGED_MODE_UPON_ANY_HANG_NO_RESET is a generic flag and 
xe_guc_exec_queue_reset_trigger_cleanup is also called from the CAT 
error path, so we should cover that as well. The best way to solve both 
issues IMO is to add a check in guc_exec_queue_timedout_job to wedge if 
XE_WEDGED_MODE_UPON_ANY_HANG_NO_RESET is set.

Daniele

>   
>   	return 0;
>   }