drm/panthor: Don't declare a queue blocked if deferred operations are pending

If deferred operations are pending, we want to wait for those to
land before declaring the queue blocked on a SYNC_WAIT. We need
this to deal with the case where the sync object is signalled through
a deferred SYNC_{ADD,SET} from the same queue. If we don't do that
and the group gets scheduled out before the deferred SYNC_{SET,ADD}
is executed, we'll end up with a timeout, because no external
SYNC_{SET,ADD} will make the scheduler reconsider the group for
execution.

Fixes: de85488 ("drm/panthor: Add the scheduler logical block")
Cc: <stable@vger.kernel.org>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240905071914.3278599-1-boris.brezillon@collabora.com

Author: bbrezillon

drivers/gpu/drm/panthor/panthor_sched.c

@@ -1103,7 +1103,13 @@ cs_slot_sync_queue_state_locked(struct panthor_device *ptdev, u32 csg_id, u32 cs
 			list_move_tail(&group->wait_node,
 				       &group->ptdev->scheduler->groups.waiting);
 		}
-		group->blocked_queues |= BIT(cs_id);
+
+		/* The queue is only blocked if there's no deferred operation
+		 * pending, which can be checked through the scoreboard status.
+		 */
+		if (!cs_iface->output->status_scoreboards)
+			group->blocked_queues |= BIT(cs_id);
+
 		queue->syncwait.gpu_va = cs_iface->output->status_wait_sync_ptr;
 		queue->syncwait.ref = cs_iface->output->status_wait_sync_value;
 		status_wait_cond = cs_iface->output->status_wait & CS_STATUS_WAIT_SYNC_COND_MASK;