From: Hans Verkuil <hans.verkuil@cisco.com> commit a4c30a4861c54af78c4eb8b7855524c1a96d9f80 upstream. When parsing the reply of a DP_REMOTE_DPCD_READ DPCD command the result is wrong due to a missing idx increment. This was never noticed since DP_REMOTE_DPCD_READ is currently not used, but if you enable it, then it is all wrong. Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Reviewed-by: Lyude Paul <lyude@redhat.com> Acked-by: Alex Deucher <alexander.deucher@amd.com> Link: https://patchwork.freedesktop.org/patch/msgid/e72ddac2-1dc0-100a-d816-9ac98a... Signed-off-by: Lee Jones <lee.jones@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- drivers/gpu/drm/drm_dp_mst_topology.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index fc97860..7c3c323 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -439,6 +439,7 @@ static bool drm_dp_sideband_parse_remote_dpcd_read(struct drm_dp_sideband_msg_rx if (idx > raw->curlen) goto fail_len; repmsg->u.remote_dpcd_read_ack.num_bytes = raw->msg[idx]; + idx++; if (idx > raw->curlen) goto fail_len; -- 1.8.3