[Intel-gfx] [PATCH v3 3/4] drm/dp/mst: Clear port->pdt when tearing down the i2c adapter

[ville.syrjala at linux.intel.com]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

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.

Clearing port->pdt in drm_dp_destroy_connector_work() would be enough,
but I chose to do it also in drm_dp_destroy_port(). The reason being
extra consistency so that we don't lose this by accident should someone
choose to refactor the code later.

v2: Cleart port->pdt in the caller, if needed (Daniel)
v3: Amend commit message a bit (Daniel)

Cc: Daniel Vetter <daniel at ffwll.ch>
Cc: stable at vger.kernel.org
Cc: Carlos Santa <carlos.santa at intel.com>
Cc: Kirill A. Shutemov <kirill at shutemov.name>
Tested-by: Carlos Santa <carlos.santa at intel.com> (v1)
Tested-by: Kirill A. Shutemov <kirill at shutemov.name> (v1)
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97666
Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 drivers/gpu/drm/drm_dp_mst_topology.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index 04e457117980..ba13f9d8720b 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -914,6 +914,7 @@ static void drm_dp_destroy_port(struct kref *kref)
 		/* 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);
 }
@@ -2919,6 +2920,7 @@ static void drm_dp_destroy_connector_work(struct work_struct *work)
 		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);
-- 
2.7.4