[SOLVED] Monitors connected to Lenovo ThinkPad Thunderbolt 3 Dock station are disabled after system startup

[przemnet]

Hello,

My setup is as follows:
* Lenovo Thinkpad T15 with Debian 12 + Cinnamon installed
* T15 is connected via Thunderbolt cable to Lenovo ThinkPad Thunderbolt 3 Dock station
* two monitors are connected to ThinkPad Thunderbolt 3 Dock via DP cables

I'm using only two external monitors, T15 lid is closed.

When I power on the laptop via dock station, Grub menu appears on both external monitors, after that when I select Debian, monitors start to blink and after some time they are disabled.

In order to get Debian working I need to
* open laptop lid
* disconnect Thunderbolt cable from the laptop
* wait for Debian to appear on laptop screen
* connect back Thunderbolt cable from the Dock to laptop
* after above operations, both external monitors are working correctly and I can close laptop lid

In 'Display settings', I have laptop screen disabled and one of external monitors is set as Primary.

In 'Power Management' settings I have:
* When the ld s closed: Do nothing (for both On A/C power and On battery power)
* Perform lid-closed action even with external monitors attached - ENABLED

Earlier I was using Linux Mint 21.1 with Cinnamon with above settings and I did not have such issues, everything was working flawlessly.

It looks that latest firmware is installed:

Code: Select all

root@T15:~# fwupdmgr get-updates
Devices with no available firmware updates: 
 • UEFI Device Firmware
 • UEFI Device Firmware
 • UEFI Device Firmware
 • UEFI Device Firmware
 • UEFI Device Firmware
 • Integrated Camera
 • ThinkPad Thunderbolt 3 Dock
 • UEFI dbx
Devices with the latest available firmware version:
 • Embedded Controller
 • Intel Management Engine
 • Intel Management Engine
 • System Firmware
 • MZVLB512HBJQ-000L7
 • Prometheus
 • Prometheus IOTA Config
No updates available
root@T15:~#

I would appreciate hints on what logs to check and how to fix the issue.

Thanks in advance.

Przemek

[mrmazda]

I don't use laptops with docking stations, so can offer little, but I noticed zero responses after more than two days. I would not expect desktop settings for displays to have any impact whatsoever on lack of screen output before and when the GUI login screen is supposed to appear on at least the primary display.

https://www.kernel.org/doc/Documentation/fb/modedb.txt explains how to use video= in Grub stanzas to configure various display parameters. Once you know the output names from Xorg.0.log or from xrandr output, they can be used to disable and/or specifically configure each display. So to disable the laptop screen you might need to include video=eDP-1:d, or force native mode on one of the external displays video=DP-1-1:2560x1440. These should take effect when KMS takes over during init, so after several seconds or more past Grub menu disappearance. They should persist on the tty framebuffers, but have no applicability in X, other than the possiblity that KMS using them for the framebuffers may cause those modes to persist when it wants to paint your login screen where you want it.

Because Mint was OK, if you haven't already, I'd report a bug about this.

[przemnet]

Hello,

I was facing problem described in initial post after netinstall from image with version 12.0.0. Few weeks ago, I reinstalled system with version 12.4.0 (image debian-12.4.0-amd64-netinst.iso) and so far, problem is not present.

Not sure what was changed, but looks it was fixed.

Cheers,
Przemek