[PATCH 2/2] drm/dp_mst: Use drm_dp_dpcd_write_data() to write GUID for non-root MST branch devices

[Imre Deak <imre.deak@intel.com>]

drm_dp_dpcd_write_data() can be used to write the GUID for a non-root
MST branch device, similarly to writing the GUID to a root MST branch
device, do so.

Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Lyude Paul <lyude@redhat.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
---
 drivers/gpu/drm/display/drm_dp_mst_topology.c | 17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c
index 619f461e02f76..a89f38fd3218b 100644
--- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
@@ -2192,20 +2192,17 @@ static int drm_dp_check_mstb_guid(struct drm_dp_mst_branch *mstb, guid_t *guid)
 	guid_copy(&mstb->guid, guid);
 
 	if (!drm_dp_validate_guid(mstb->mgr, &mstb->guid)) {
+		struct drm_dp_aux *aux;
 		u8 buf[UUID_SIZE];
 
 		export_guid(buf, &mstb->guid);
 
-		if (mstb->port_parent) {
-			ret = drm_dp_send_dpcd_write(mstb->mgr,
-						     mstb->port_parent,
-						     DP_GUID, sizeof(buf), buf);
-			if (ret >= 0)
-				ret = ret == sizeof(buf) ? 0 : -EPROTO;
-		} else {
-			ret = drm_dp_dpcd_write_data(mstb->mgr->aux,
-						     DP_GUID, buf, sizeof(buf));
-		}
+		if (mstb->port_parent)
+			aux = &mstb->port_parent->aux;
+		else
+			aux = mstb->mgr->aux;
+
+		ret = drm_dp_dpcd_write_data(aux, DP_GUID, buf, sizeof(buf));
 	}
 
 	return ret;
-- 
2.44.2