[PATCH v2 2/3] drm/panthor: Report group as timedout when we fail to properly suspend

[Steven Price]

On 28/10/2024 11:48, Boris Brezillon wrote:
> If we don't do that, the group is considered usable by userspace, but
> all further GROUP_SUBMIT will fail with -EINVAL.
> 
> Changes in v2:
> - New patch
> 
> Fixes: de8548813824 ("drm/panthor: Add the scheduler logical block")
> Signed-off-by: Boris Brezillon <boris.brezillon at collabora.com>

I guess a failure to suspend is close enough to a time out. I think the
only case that might actually matter is dealt with by your next patch.

Reviewed-by: Steven Price <steven.price at arm.com>

> ---
>  drivers/gpu/drm/panthor/panthor_sched.c | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/panthor/panthor_sched.c b/drivers/gpu/drm/panthor/panthor_sched.c
> index eda8fbb276b3..ef4bec7ff9c7 100644
> --- a/drivers/gpu/drm/panthor/panthor_sched.c
> +++ b/drivers/gpu/drm/panthor/panthor_sched.c
> @@ -602,10 +602,11 @@ struct panthor_group {
>  	 * @timedout: True when a timeout occurred on any of the queues owned by
>  	 * this group.
>  	 *
> -	 * Timeouts can be reported by drm_sched or by the FW. In any case, any
> -	 * timeout situation is unrecoverable, and the group becomes useless.
> -	 * We simply wait for all references to be dropped so we can release the
> -	 * group object.
> +	 * Timeouts can be reported by drm_sched or by the FW. If a reset is required,
> +	 * and the group can't be suspended, this also leads to a timeout. In any case,
> +	 * any timeout situation is unrecoverable, and the group becomes useless. We
> +	 * simply wait for all references to be dropped so we can release the group
> +	 * object.
>  	 */
>  	bool timedout;
>  
> @@ -2687,6 +2688,12 @@ void panthor_sched_suspend(struct panthor_device *ptdev)
>  		csgs_upd_ctx_init(&upd_ctx);
>  		while (slot_mask) {
>  			u32 csg_id = ffs(slot_mask) - 1;
> +			struct panthor_csg_slot *csg_slot = &sched->csg_slots[csg_id];
> +
> +			/* We consider group suspension failures as fatal and flag the
> +			 * group as unusable by setting timedout=true.
> +			 */
> +			csg_slot->group->timedout = true;
>  
>  			csgs_upd_ctx_queue_reqs(ptdev, &upd_ctx, csg_id,
>  						CSG_STATE_TERMINATE,