Bug 109795 - Thunderbolt display not detected
Summary: Thunderbolt display not detected
Alias: None
Product: DRI
Classification: Unclassified
Component: DRM/Intel (show other bugs)
Version: XOrg git
Hardware: x86-64 (AMD64) Linux (All)
: medium normal
Assignee: Intel GFX Bugs mailing list
QA Contact: Intel GFX Bugs mailing list
Whiteboard: Triaged
Depends on:
Reported: 2019-02-28 07:37 UTC by Max Richter
Modified: 2019-07-26 06:53 UTC (History)
1 user (show)

See Also:
i915 platform: KBL
i915 features:

dmesg_xrandr_lspci_lsusb_logs (112.95 KB, application/zip)
2019-02-28 07:37 UTC, Max Richter
no flags Details

Note You need to log in before you can comment on or make changes to this bug.
Description Max Richter 2019-02-28 07:37:20 UTC
Created attachment 143493 [details]

I am using a Dell XPS 13 (9370) connected to a Caldigit TS3 Plus thunderbolt dock. On this dock I have two monitors connected. One is connected to the display port of the dock, the second one is connected to an USB-C Thunderbolt port using an USB-C to mini DP adapter.

The second monitor is only detected, when I _first_ plug in the adapter and _then_ plug in the the cable to the adapter. This also only works when the system has booted _and_ I am logged in. I already disabled thunderbolt security completely in UEFI. Once the monitor has been detected it is also working during boot, when I restart the system. This also appears when directly plugging in the adapter to a Thunderbolt port of the laptop.

I can reproduce the issue also with latest DRM-tip kernel 

I Reported this bug already to Ubuntu kernel: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1817070
Comment 1 Lakshmi 2019-07-03 08:40:31 UTC
Repoerter, Can you please verify the issue with drmtip (https://cgit.freedesktop.org/drm-tip) and kernel parameters drm.debug=0x1e log_buf_len=4M, and if the problem persists attach the full dmesg from boot.
Comment 2 Max Richter 2019-07-26 06:53:14 UTC
Hi, I replaced the cable to not use the adapter any more and now it works. So this issue can be closed.

Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.