[PATCH v5 1/2] drm/panthor: Reset queue slots if termination fails

[Liviu Dudau]

On Tue, Jun 03, 2025 at 10:49:31AM +0100, Ashley Smith wrote:
> This fixes a bug where if we timeout after a suspend and the termination
> fails, due to waiting on a fence that will never be signalled for
> example, we do not resume the group correctly. The fix forces a reset
> for groups that are not terminated correctly.

I have a question on the commit message: you're describing a situation where
a fence will *never* be signalled. Is that a real example? I thought this is
not supposed to ever happen! Or are you trying to say that the fence signalling
happens after the timeout?

> 
> Signed-off-by: Ashley Smith <ashley.smith at collabora.com>
> Fixes: de8548813824 ("drm/panthor: Add the scheduler logical block")
> ---
>  drivers/gpu/drm/panthor/panthor_sched.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/panthor/panthor_sched.c b/drivers/gpu/drm/panthor/panthor_sched.c
> index 43ee57728de5..65d8ae3dcac1 100644
> --- a/drivers/gpu/drm/panthor/panthor_sched.c
> +++ b/drivers/gpu/drm/panthor/panthor_sched.c
> @@ -2727,8 +2727,17 @@ void panthor_sched_suspend(struct panthor_device *ptdev)
>  			 * automatically terminate all active groups, so let's
>  			 * force the state to halted here.
>  			 */
> -			if (csg_slot->group->state != PANTHOR_CS_GROUP_TERMINATED)
> +			if (csg_slot->group->state != PANTHOR_CS_GROUP_TERMINATED) {
>  				csg_slot->group->state = PANTHOR_CS_GROUP_TERMINATED;
> +
> +				/* Reset the queue slots manually if the termination
> +				 * request failed.
> +				 */
> +				for (i = 0; i < group->queue_count; i++) {
> +					if (group->queues[i])
> +						cs_slot_reset_locked(ptdev, csg_id, i);
> +				}
> +			}
>  			slot_mask &= ~BIT(csg_id);
>  		}
>  	}
> -- 
> 2.43.0
> 

Reviewed-by: Liviu Dudau <liviu.dudau at arm.com>

Best regards,
Liviu

-- 
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