The commit message should be shorter and follow the format other commits for drm usually do, in this case something like:

drm/dp_mst: Retrieve extended DPCD caps for topology manager

On Thu, 2020-09-10 at 14:36 +0800, Koba Ko wrote:

As per DP-1.3, First check DP_EXTENDED_RECEIVER_CAP_FIELD_PRESENT. If DP_EXTENDED_RECEIVER_CAP_FIELD_PRESENT is 1, read the DP_DP13_DPCD_REV to get the faster capability. If DP_EXTENDED_RECEIVER_CAP_FIELD_PRESENT is 0, read DP_DPCD_REV.

Signed-off-by: Koba Ko koba.ko@canonical.com

ChangeLog:

1. use drm_dp_read_dpcd_caps instead.

---

drivers/gpu/drm/drm_dp_mst_topology.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index 7753c718ddf9..293f71d0ae90 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -3694,8 +3694,8 @@ int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool ms ((dpcd_ext & DP_EXTENDED_RECEIVER_CAP_FIELD_PRESENT) ? DP_DP13_DPCD_REV : DP_DPCD_REV);

/* get dpcd info */

• ret = drm_dp_dpcd_read(mgr->aux, dpcd_offset, mgr->dpcd,
  

DP_RECEIVER_CAP_SIZE);

• if (ret != DP_RECEIVER_CAP_SIZE) {
  

• ret = drm_dp_read_dpcd_caps(mgr->aux, mgr->dpcd);
  

• if (ret < 0) {
  DRM_DEBUG_KMS("failed to read DPCD\n");
  

Let's use drm_dbg_kms() here, and let's also print the return code when this fails.

With those things fixed:

Reviewed-by: Lyude Paul lyude@redhat.com

	goto out_unlock;
}