drm_dp_mst_topology: fix broken drm_dp_sideband_parse_remote_dpcd_read()

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-d816-9ac98ac009dd@xs4all.nl
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index e05dda92398c6e5bc1f77580f381800ac1c430cb..592ebcd440b6de617de6bb25ac6128f61eef4e72 100644 (file)
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -431,6 +431,7 @@ 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;