[PATCH 1/5] drm/bridge: lt9611c: fallback to cached HPD status on read failure

[mohit.dsor@oss.qualcomm.com]

From: Mohit Dsor <mohit.dsor@oss.qualcomm.com>

HPD status is retrieved via an MCU command. In some cases the
command may fail, for example when the MCU is not yet ready,
leading to incorrect disconnect reporting.

Instead of returning an error state, fall back to the last known
HPD status to provide a more stable detection result.

This avoids spurious disconnect events during initialization.

Signed-off-by: Mohit Dsor <mohit.dsor@oss.qualcomm.com>
---
 drivers/gpu/drm/bridge/lontium-lt9611c.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/bridge/lontium-lt9611c.c b/drivers/gpu/drm/bridge/lontium-lt9611c.c
index 5d67bb7391fb..81ca9d62eae3 100644
--- a/drivers/gpu/drm/bridge/lontium-lt9611c.c
+++ b/drivers/gpu/drm/bridge/lontium-lt9611c.c
@@ -711,10 +711,12 @@ lt9611c_bridge_detect(struct drm_bridge *bridge, struct drm_connector *connector
 	guard(mutex)(&lt9611c->ocm_lock);
 
 	ret = lt9611c_read_write_flow(lt9611c, cmd, ARRAY_SIZE(cmd), data, ARRAY_SIZE(data));
-	if (ret)
+	if (ret) {
 		dev_err(dev, "failed to read HPD status (err=%d)\n", ret);
-	else
+		connected = lt9611c->hdmi_connected;
+	} else {
 		connected = (data[4] == 0x02);
+	}
 
 	lt9611c->hdmi_connected = connected;
 
-- 
2.34.1