[PATCH v2 4/4] drm/dp_mst: Print errors on ACT timeouts

From: Lyude Paul
Date: Mon Apr 06 2020 - 18:13:17 EST


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@xxxxxxxxxx>
Cc: Sean Paul <sean@xxxxxxxxxx>
---
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 ce61964baa7c..0cbeb0f5c834 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -4499,10 +4499,14 @@ int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr)
status & DP_PAYLOAD_ACT_HANDLED || status < 0,
100, timeout_ms * USEC_PER_MSEC);
if (ret < 0 && status >= 0) {
- 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;
} else if (status < 0) {
+ /*
+ * Failure here isn't unexpected - the hub may have
+ * just been unplugged
+ */
DRM_DEBUG_KMS("Failed to read payload table status: %d\n",
status);
return status;
--
2.25.1