6.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
commit 7a1f30afe97294281a2ba05977688385744f9844 upstream.
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: de8548813824 ("drm/panthor: Add the scheduler logical block")
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
Reviewed-by: Steven Price <steven.price@xxxxxxx>
Reviewed-by: Liviu Dudau <liviu.dudau@xxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20240905071914.3278599-1-boris.brezillon@xxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/panthor/panthor_sched.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/panthor/panthor_sched.c b/drivers/gpu/drm/panthor/panthor_sched.c
index 145d983bb129..2aff02ba6949 100644
--- a/drivers/gpu/drm/panthor/panthor_sched.c
+++ b/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;
--
2.46.2
