Patch "drm/dp/mst: Clear port->pdt when tearing down the i2c adapter" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

    drm/dp/mst: Clear port->pdt when tearing down the i2c adapter

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
drm-dp-mst-clear-port-pdt-when-tearing-down-the-i2c-adapter.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <[email protected]>
Date: Wed, 26 Oct 2016 16:30:33 +0300
Subject: drm/dp/mst: Clear port->pdt when tearing down the i2c adapter
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From: Ville Syrjälä <[email protected]>

commit 36e3fa6a38e135e9478a2f75dec9bf6ff1e6480e upstream.

The i2c adapter is only relevant for some peer device types, so let's clear the pdt if it's still the same as the old_pdt when we tear down the i2c adapter.

I don't really like this design pattern of updating port->whatever before doing the accompanying changes and passing around old_whatever to figure stuff out. Would make much more sense to me to the pass the new value around and only update the port->whatever when things are consistent. But let's try to work with what we have right now.

Quoting a follow-up from Ville:

"And naturally I forgot to amend the commit message w.r.t. this guy [the change in drm_dp_destroy_port]. We don't really need to do this here, but I figured I'd try to be a bit more consistent by having it, just to avoid accidental mistakes if/when someone changes this stuff again later."

v2: Clear port->pdt in the caller, if needed (Daniel)

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97666

---
 drivers/gpu/drm/drm_dp_mst_topology.c |    2 ++
 1 file changed, 2 insertions(+)

@@ -909,6 +909,7 @@ static void drm_dp_destroy_port(struct k
 		/* no need to clean up vcpi
 		 * as if we have no connector we never setup a vcpi */
 		drm_dp_port_teardown_pdt(port, port->pdt);
+		port->pdt = DP_PEER_DEVICE_NONE;
 	}
 	kfree(port);
 }

@@ -2872,6 +2873,7 @@ static void drm_dp_destroy_connector_wor
 		mgr->cbs->destroy_connector(mgr, port->connector);
 
 		drm_dp_port_teardown_pdt(port, port->pdt);
+		port->pdt = DP_PEER_DEVICE_NONE;
 
 		if (!port->input && port->vcpi.vcpi > 0) {
 			drm_dp_mst_reset_vcpi_slots(mgr, port);

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/drm-dp-mst-clear-port-pdt-when-tearing-down-the-i2c-adapter.patch