Screen on usb-c docker hard to turn on - i915 & xrandr - thinkpad x1 6th gen

Asked by Arthur Lutz (Logilab) on 2020-06-24

Since upgrading to focal I'm having trouble with the HDMI screen that is plugged in to my USB-C dock (`VMM3332 inside Dell WD15/TB16/TB18 wired Dock`)

When booting I get only the screen on the laptop, although the HDMI screen is visible in `xrandr` and the displays tool. Changing resolutions doesn't solve the problem.

Resetting and restarting the dock can end up getting the screen to work. Another weird behaviour was it turned on when I plugged into the laptop's HDMI port an adapter to VGA (without a cable on the end of it). Detecting a third screen got it to work.

I can't seem to find relevant information in the **Xorg.log** or **xrandr** output or `fwupdmgr get-devices`. Could this be related to **thunderbolt**? (no more logs in `dmesg` for that...) How can I check that I'm using the `i915` driver correctly ?

I can provide xrandr outputs for the various trial'n'errors. Sorry for this quite open question, I can't seem to find a way to tackle this bug.

dmesg related to i915 : and boltd messages in syslog :

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Does the system have a make and model? Do you have the latest BIOS?

Thanks for taking a look at this !

dmidecode states :

        Manufacturer: LENOVO
        Product Name: 20KH006JFR
        Version: ThinkPad X1 Carbon 6th

Not sure how to check if I have the latest BIOS. I'm reading to see if I need to upgrade (have used fwupmgr recently to upgrade firmwares).

There seems to be an update available, but is is significant ?

  fwupdmgr update
  • Thunderbolt Controller has the latest available firmware version
  • System Firmware has the latest available firmware version
  • THNSN5512GPUK NVMe TOSHIBA 512GB has no available firmware updates
  Upgrade available for UEFI Device Firmware from 184.70.3626 to 184.77.3664

Launchpad Janitor (janitor) said : #4

This question was expired because it remained in the 'Open' state without activity for the last 15 days.