From 8605e8573eae0457d6d3a1826ba3253e56c3d644 Mon Sep 17 00:00:00 2001 From: Mykola Lysenko Date: Fri, 25 Dec 2015 16:14:47 +0800 Subject: [PATCH] drm/dp/mst: fix in MSTB RAD initialization [ Upstream commit 75af4c8c4c0f60d7ad135419805798f144e9baf9 ] This fix is needed to support more then two branch displays, so RAD address consist at least of 2 elements Acked-by: Dave Airlie Signed-off-by: Mykola Lysenko Signed-off-by: Alex Deucher Cc: stable@vger.kernel.org Signed-off-by: Sasha Levin --- drivers/gpu/drm/drm_dp_mst_topology.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index c511057..c7c1e1f 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -968,17 +968,17 @@ static struct drm_dp_mst_port *drm_dp_get_port(struct drm_dp_mst_branch *mstb, u static u8 drm_dp_calculate_rad(struct drm_dp_mst_port *port, u8 *rad) { - int lct = port->parent->lct; + int parent_lct = port->parent->lct; int shift = 4; - int idx = lct / 2; - if (lct > 1) { - memcpy(rad, port->parent->rad, idx); - shift = (lct % 2) ? 4 : 0; + int idx = (parent_lct - 1) / 2; + if (parent_lct > 1) { + memcpy(rad, port->parent->rad, idx + 1); + shift = (parent_lct % 2) ? 4 : 0; } else rad[0] = 0; rad[idx] |= port->port_num << shift; - return lct + 1; + return parent_lct + 1; } /* -- 2.7.4