4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Sean Paul <[email protected]>

[ Upstream commit 5f3417569165a8ee57654217f73e0160312f409c ]

The bridge loses its hw state when the cable is unplugged. If we detect
this case in the hpd handler, reset its state.

Reported-by: Rob Clark <[email protected]>
Tested-by: Rob Clark <[email protected]>
Reviewed-by: Archit Taneja <[email protected]>
Signed-off-by: Sean Paul <[email protected]>
Link: 
https://patchwork.freedesktop.org/patch/msgid/[email protected]
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
 drivers/gpu/drm/i2c/adv7511.c |   12 ++++++++++++
 1 file changed, 12 insertions(+)

--- a/drivers/gpu/drm/i2c/adv7511.c
+++ b/drivers/gpu/drm/i2c/adv7511.c
@@ -450,6 +450,18 @@ static void adv7511_hpd_work(struct work
        else
                status = connector_status_disconnected;
 
+       /*
+        * The bridge resets its registers on unplug. So when we get a plug
+        * event and we're already supposed to be powered, cycle the bridge to
+        * restore its state.
+        */
+       if (status == connector_status_connected &&
+           adv7511->connector.status == connector_status_disconnected &&
+           adv7511->powered) {
+               regcache_mark_dirty(adv7511->regmap);
+               adv7511_power_on(adv7511);
+       }
+
        if (adv7511->connector.status != status) {
                adv7511->connector.status = status;
                drm_kms_helper_hotplug_event(adv7511->connector.dev);


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