Re: [PATCH 4/4] drm/dp_mst: Print errors on ACT timeouts

On Fri, Apr 3, 2020 at 4:08 PM Lyude Paul lyude@redhat.com wrote:

Although it's not unexpected for drm_dp_check_act_status() to fail due to DPCD read failures (as the hub may have just been unplugged suddenly), timeouts are a bit more worrying as they either mean we need a longer timeout value, or we aren't setting up payload allocations properly. So, let's start printing errors on timeouts.

Signed-off-by: Lyude Paul lyude@redhat.com Cc: Sean Paul sean@poorly.run

Reviewed-by: Sean Paul sean@poorly.run

---

drivers/gpu/drm/drm_dp_mst_topology.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index f313407374ed..3d0d373f6f91 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -4494,6 +4494,10 @@ int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr) DP_PAYLOAD_TABLE_UPDATE_STATUS, &status); if (ret < 0) {

•                   /*
  

•                    * Failure here isn't unexpected - the hub may have
  

•                    * just been unplugged
  

•                    */
                    DRM_DEBUG_KMS("failed to read payload table status %d\n",
                                  ret);
                    return ret;
  

@@ -4505,8 +4509,8 @@ int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr) } while (jiffies < timeout);

    if (!(status & DP_PAYLOAD_ACT_HANDLED)) {

•           DRM_DEBUG_KMS("failed to get ACT bit %d after %dms\n",
  

•                         status, timeout_ms);
  

•           DRM_ERROR("Failed to get ACT after %dms, last status: %02x\n",
  

•                     timeout_ms, status);
            return -EINVAL;
    }
    return 0;
  

-- 2.25.1