[PATCH] drm/rockchip: cdn-dp: Use drm_connector_helper_hpd_irq_event()

[Thomas Zimmermann]

The code for detecting and updating the connector status in
cdn_dp_pd_event_work() has a number of problems.

- It does not aquire the locks to call the detect helper and update
the connector status. These are struct drm_mode_config.connection_mutex
and struct drm_mode_config.mutex.

- It does not use drm_helper_probe_detect(), which helps with the
details of locking and detection.

- It uses the connector's status field to determine a change to
the connector status. The epoch_counter field is the correct one. The
field signals a change even if the connector status' value did not
change.

Replace the code with a call to drm_connector_helper_hpd_irq_event(),
which fixes all these problems.

Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
Fixes: 81632df69772 ("drm/rockchip: cdn-dp: do not use drm_helper_hpd_irq_event")
Cc: Chris Zhong <zyw at rock-chips.com>
Cc: Guenter Roeck <groeck at chromium.org>
Cc: Sandy Huang <hjc at rock-chips.com>
Cc: "Heiko Stübner" <heiko at sntech.de>
Cc: Andy Yan <andy.yan at rock-chips.com>
Cc: dri-devel at lists.freedesktop.org
Cc: linux-arm-kernel at lists.infradead.org
Cc: linux-rockchip at lists.infradead.org
Cc: <stable at vger.kernel.org> # v4.11+
---
 drivers/gpu/drm/rockchip/cdn-dp-core.c | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/rockchip/cdn-dp-core.c b/drivers/gpu/drm/rockchip/cdn-dp-core.c
index b04538907f95..f576b1aa86d1 100644
--- a/drivers/gpu/drm/rockchip/cdn-dp-core.c
+++ b/drivers/gpu/drm/rockchip/cdn-dp-core.c
@@ -947,9 +947,6 @@ static void cdn_dp_pd_event_work(struct work_struct *work)
 {
 	struct cdn_dp_device *dp = container_of(work, struct cdn_dp_device,
 						event_work);
-	struct drm_connector *connector = &dp->connector;
-	enum drm_connector_status old_status;
-
 	int ret;
 
 	mutex_lock(&dp->lock);
@@ -1009,11 +1006,7 @@ static void cdn_dp_pd_event_work(struct work_struct *work)
 
 out:
 	mutex_unlock(&dp->lock);
-
-	old_status = connector->status;
-	connector->status = connector->funcs->detect(connector, false);
-	if (old_status != connector->status)
-		drm_kms_helper_hotplug_event(dp->drm_dev);
+	drm_connector_helper_hpd_irq_event(&dp->connector);
 }
 
 static int cdn_dp_pd_event(struct notifier_block *nb,
-- 
2.47.0