[PATCH v3 2/3] drm/vc4: hdmi: always cancel the scrambling work synchronously

[Lucas Tanure <lucas.tanure@neat.no>]

The scrambling work re-arms itself every second while a scrambled mode
is active. When the output is disabled, the work may be executing at
that moment rather than pending, and delayed_work_pending() is then
false, so the cancel is skipped. The running instance finishes after
the disable, sees the sink report scrambling off, writes the SCDC
scrambling and clock ratio bits back on, and queues itself again. The
sink is left configured for a scrambled 1/40 link that no longer exists
and the work keeps running until the next enable.

cancel_delayed_work_sync() handles both states: it waits for a running
instance and blocks it from queueing itself again.

Fixes: 257d36d493e9 ("drm/vc4: hdmi: Add a workqueue to set scrambling")
Assisted-by: LLM
Signed-off-by: Lucas Tanure <lucas.tanure@neat.no>
Reviewed-by: Maíra Canal <mcanal@igalia.com>
---
 drivers/gpu/drm/vc4/vc4_hdmi.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index 2cc46036f11d..4a386e053d3f 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -843,8 +843,7 @@ static void vc4_hdmi_disable_scrambling(struct drm_encoder *encoder)
 
 	vc4_hdmi->scdc_enabled = false;
 
-	if (delayed_work_pending(&vc4_hdmi->scrambling_work))
-		cancel_delayed_work_sync(&vc4_hdmi->scrambling_work);
+	cancel_delayed_work_sync(&vc4_hdmi->scrambling_work);
 
 	if (!drm_dev_enter(drm, &idx))
 		return;
-- 
2.56.0