general protection fault, external monitor

Hi all, long time Lubuntu and Ubuntu + lubuntu-desktop user (okay probably only since 14.04), first post.

I installed Lubuntu 20.04 (ISO from lubuntu .me) on my new ThinkPad X1 Carbon gen7, and it was plain sailing, with and without the external monitor attached direct via HDMI.

I then found out how to get my Lenovo Thunderbolt 3 dock working via - this works, somewhat, allowing me to connect via DisplayPort or USB-C from the dock to the monitor, then USB-C from laptop to dock. Multiple times a day however, I am kicked back to login screen. Coinciding with this is an entry in dmesg, kern.log or syslog general protection fault ... from either lxqt-globalkeys or Core. It appears to be when the display is busier - Youtube videos, videoconferencing, or switching (with the keyboard) between displays. Curiously, the keyboard shortcut I mostly used to switch between desktops is defined in ~/.config/openbox/lxqt-rc.xml and not l ~/.config/lxqt/globalkeyshortcuts.conf.

I have compiled hardware information and the errors from today at

Can someone suggest how I go about troubleshooting this? Is it a bug I can report somewhere?


You should absolutely be going to the DisplayLink folks for support, since everything worked fine until you introduced that. The issue lies there somewhere. No one except the producers of proprietary software can be expected to reasonably support it.

That said, I see a bunch of known issues that might be relevant here. Also, looking at the release notes, the minimum X server version is 1.16. What that means, I don’t know because the whole X stack is currently at 7.7 (this can be thought of as a distribution, where it includes components with completely different version numbers, but they call it a katamari), but includes the X server version 1.12.2.

Finally, I know of no process that would run as “Core,” so that’s maybe this DisplayLink business?

Thank you for the advice. I have posted at and will see if I get any bites.

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