When I plug my Lenovo ThinkPad T490 in to my LG 32UL950 via Thunderbolt 3, the following messages are repeated in journalctl 8 times/second:

Feb 04 09:12:46 <hostname> kernel: ACPI BIOS Error (bug): Could not resolve symbol [\_SB.PCI0.RP09.PEGP.NVDN], AE_NOT_FOUND (20210730/psargs-330)
Feb 04 09:12:46 <hostname> kernel: 
Feb 04 09:12:46 <hostname> kernel: No Local Variables are initialized for Method [_Q27]
Feb 04 09:12:46 <hostname> kernel: 
Feb 04 09:12:46 <hostname> kernel: No Arguments are initialized for method [_Q27]
Feb 04 09:12:46 <hostname> kernel: 
Feb 04 09:12:46 <hostname> kernel: ACPI Error: Aborting method \_SB.PCI0.LPCB.EC._Q27 due to previous error (AE_NOT_FOUND) (20210730/psparse-529)

The power (as reported from while true; do cat /sys/class/power_supply/AC/online; done) flickers on and off, and the battery drains pretty quickly.

This started sometime within the past week or two and makes it very inconvenient to use this monitor.

System information:

$ lsb_release -a
LSB Version:    core-11.1.0ubuntu4-noarch:security-11.1.0ubuntu4-noarch
Distributor ID: Ubuntu
Description:    Ubuntu 22.04.1 LTS
Release:    22.04
Codename:   jammy
$ uname -a
Linux <hostname> 5.15.0-60-generic #66-Ubuntu SMP Fri Jan 20 14:29:49 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux

2 Answers 2


There's an Ubuntu bug report. According to this posting in Ask Ubuntu community this affects several kernels (5.12 and 5.17 mentioned) and there's also a kernel.org bug report. The kernel.org posting contains link to a potential fix.


I was able to eliminate the problem with a firmware update:

sudo fwupdmgr get-updates && sudo fwupdmgr update
sudo reboot now
# press a key when instructed at boot
# and wait a few minutes while it updates without showing any progress
  • I did the same and upgraded everything on Thinkpad T590, but still have randomly the same problems when connecting AC power. In my case it looks more like a flaky connector, with another charger it works flawlessly and worked even before the update.
    – tla
    Jan 4 at 17:30

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .