LG Gram 12gen high CPU use when USB-C/TB is in use

[rustyx]

LG Gram laptop 17Z90Q with a Core i7-1260P CPU.

Whenever an external monitor is connected to USB-C/Thunderbolt 4, average load goes above 3.0 and the machine is getting very hot.

Output from top -H shows a lot of kworker CPU usage:

top - 11:45:06 up 33 min, 2 users, load average: 3,30, 3,08, 2,79
Threads: 1442 total, 2 running, 1440 sleeping, 0 stopped, 0 zombie
%Cpu(s): 0,1 us, 3,7 sy, 0,0 ni, 96,1 id, 0,0 wa, 0,0 hi, 0,1 si, 0,0 st
MiB Mem : 15684,6 total, 8510,2 free, 2580,8 used, 4593,6 buff/cache
MiB Swap: 3815,0 total, 3815,0 free, 0,0 used. 11326,9 avail Mem

    PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ WCHAN COMMAND
   7766 root 20 0 0 0 0 R 19,8 0,0 0:56.05 worker_th+ kworker/0:2-events
    196 root 20 0 0 0 0 D 15,8 0,0 1:18.12 ec_guard kworker/u32:2+USBC000:00-con0
  10237 root 20 0 0 0 0 I 12,9 0,0 0:26.44 worker_th+ kworker/0:0-events
   1027 root 20 0 0 0 0 I 6,6 0,0 0:43.30 worker_th+ kworker/1:3-events
  10971 root 20 0 0 0 0 I 4,0 0,0 0:00.20 worker_th+ kworker/15:0-events
    175 root 20 0 0 0 0 I 2,3 0,0 0:03.24 worker_th+ kworker/11:1-events
   2410 root 20 0 0 0 0 I 1,7 0,0 0:05.49 worker_th+ kworker/9:3-events

Perf shows a lot of time spent inside handle_irq_event/acpi_ev_gpe_detect/acpi_hw_gpe_read.

Additionally, kernel log is getting spammed with these lines every 4 seconds (but also without any USB-C device attached):

[ 223.514304] ACPI Error: No handler for Region [XIN1] (00000000f2ad4f1f) [UserDefinedRegion] (20210730/evregion-130)
[ 223.514323] ACPI Error: Region UserDefinedRegion (ID=143) has no handler (20210730/exfldio-261)

[ 223.514337]
               Initialized Local Variables for Method [_TMP]:
[ 223.514339] Local0: 0000000021495082 <Obj> Integer 0000000000000034

[ 223.514349] No Arguments are initialized for method [_TMP]

[ 223.514354] ACPI Error: Aborting method \_SB.PC00.LPCB.LGEC.SEN2._TMP due to previous error (AE_NOT_EXIST) (20210730/psparse-529)

ProblemType: Bug
DistroRelease: Ubuntu 22.04
Package: linux-image-5.15.0-46-generic 5.15.0-46.49
ProcVersionSignature: Ubuntu 5.15.0-46.49-generic 5.15.39
Uname: Linux 5.15.0-46-generic x86_64
ApportVersion: 2.20.11-0ubuntu82.1
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: me 1678 F.... pulseaudio
 /dev/snd/controlC1: me 1678 F.... pulseaudio
CRDA: N/A
CasperMD5CheckResult: pass
Date: Fri Aug 26 11:57:05 2022
InstallationDate: Installed on 2022-08-25 (1 days ago)
InstallationMedia: Ubuntu 22.04.1 LTS "Jammy Jellyfish" - Release amd64 (20220809.1)
MachineType: LG Electronics 17Z90Q-G.AA78N
ProcFB: 0 i915drmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.15.0-46-generic root=UUID=e2f96916-a67c-432e-b687-730071271216 ro quiet splash vt.handoff=7
PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No PulseAudio daemon running, or not running as session daemon.
RelatedPackageVersions:
 linux-restricted-modules-5.15.0-46-generic N/A
 linux-backports-modules-5.15.0-46-generic N/A
 linux-firmware 20220329.git681281e4-0ubuntu3.4
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 07/06/2022
dmi.bios.release: 0.1
dmi.bios.vendor: Phoenix Technologies Ltd.
dmi.bios.version: A1ZG0380 X64
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.name: 17Z90Q
dmi.board.vendor: LG Electronics
dmi.board.version: FAB1
dmi.chassis.asset.tag: Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: LG Electronics
dmi.chassis.version: 0.1
dmi.ec.firmware.release: 33.0
dmi.modalias: dmi:bvnPhoenixTechnologiesLtd.:bvrA1ZG0380X64:bd07/06/2022:br0.1:efr33.0:svnLGElectronics:pn17Z90Q-G.AA78N:pvr0.1:rvnLGElectronics:rn17Z90Q:rvrFAB1:cvnLGElectronics:ct10:cvr0.1:skuEVO:
dmi.product.family: LG gram PC
dmi.product.name: 17Z90Q-G.AA78N
dmi.product.sku: EVO
dmi.product.version: 0.1
dmi.sys.vendor: LG Electronics

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This change was made by a bot.

[rustyx (rustyx2)]

Note: first booting into Windows 11 and then rebooting into Ubuntu "fixes" it.

Threads: 656 total, 2 running, 654 sleeping, 0 stopped, 0 zombie
%Cpu(s): 0,1 us, 0,1 sy, 0,0 ni, 99,7 id, 0,0 wa, 0,0 hi, 0,0 si, 0,0 st
MiB Mem : 15684,6 total, 12946,2 free, 793,6 used, 1944,7 buff/cache
MiB Swap: 3815,0 total, 3815,0 free, 0,0 used. 13710,5 avail Mem

    PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ WCHAN COMMAND
   3019 root 20 0 22284 4440 3380 R 0,3 0,0 0:00.03 - top
    197 root 20 0 0 0 0 I 0,3 0,0 0:00.23 - kworker/u32:3-events_unbound
      1 root 20 0 166812 11948 8256 S 0,0 0,1 0:01.82 ep_poll systemd
      2 root 20 0 0 0 0 S 0,0 0,0 0:00.00 kthreadd kthreadd
      3 root 0 -20 0 0 0 I 0,0 0,0 0:00.00 rescuer_t+ rcu_gp
      4 root 0 -20 0 0 0 I 0,0 0,0 0:00.00 rescuer_t+ rcu_par_gp
      5 root 0 -20 0 0 0 I 0,0 0,0 0:00.00 rescuer_t+ netns
      6 root 20 0 0 0 0 I 0,0 0,0 0:00.41 worker_th+ kworker/0:0-events
      7 root 0 -20 0 0 0 I 0,0 0,0 0:00.00 worker_th+ kworker/0:0H-events_highpri
      8 root 20 0 0 0 0 I 0,0 0,0 0:00.42 worker_th+ kworker/0:1-cgroup_destroy
      9 root 20 0 0 0 0 I 0,0 0,0 0:00.29 worker_th+ kworker/u32:0-loop6

[rustyx (rustyx2)]

Here are some ACPI event traces:

echo 0x0f > /sys/module/acpi/parameters/debug_layer
echo 0x0f > /sys/module/acpi/parameters/debug_level

[ 2432.074662] evmisc-0132 ev_queue_notify_reques: Dispatching Notify on [UBTC] (Device) Value 0x80 (Status Change) Node 00000000c4abd855
[ 2432.126632] ACPI Debug: 0x00000000000000E0
[ 2432.171756] ACPI Debug: "UBTC._DSM(2)"
[ 2432.242916] ACPI Debug: "_Q79"
[ 2432.246137] ACPI Debug: "_Q79"
[ 2432.247420] ACPI Debug: "UCEV"
[ 2432.287432] ACPI Debug: "UBTC._DSM(2)"
[ 2432.394856] evmisc-0132 ev_queue_notify_reques: Dispatching Notify on [UBTC] (Device) Value 0x80 (Status Change) Node 00000000c4abd855
[ 2432.397313] ACPI Debug: "UCEV"
[ 2432.481271] ACPI Debug: "UBTC._DSM(2)"
[ 2432.582744] evmisc-0132 ev_queue_notify_reques: Dispatching Notify on [UBTC] (Device) Value 0x80 (Status Change) Node 00000000c4abd855
[ 2432.664302] ACPI Debug: "UBTC._DSM(2)"
[ 2432.752154] ACPI Debug: "UBTC._DSM(2)"
[ 2432.840088] ACPI Debug: "UBTC._DSM(1)"
[ 2433.071576] ACPI Debug: 0x00000000000000E0
[ 2433.110414] ACPI Debug: "UBTC._DSM(1)"
[ 2433.118887] ACPI Debug: "_Q79"
[ 2433.119819] ACPI Debug: "UCEV"
[ 2433.198510] ACPI Debug: "_Q79"
[ 2433.371280] ACPI Debug: 0x00000000000000E0
[ 2433.474478] evmisc-0132 ev_queue_notify_reques: Dispatching Notify on [UBTC] (Device) Value 0x80 (Status Change) Node 00000000c4abd855
[ 2433.476980] ACPI Debug: "UCEV"
[ 2433.502853] ACPI Debug: "UBTC._DSM(2)"
[ 2433.509903] ACPI Debug: "_Q79"
[ 2433.594694] ACPI Debug: "_Q79"
[ 2433.626579] evmisc-0132 ev_queue_notify_reques: Dispatching Notify on [UBTC] (Device) Value 0x80 (Status Change) Node 00000000c4abd855
[ 2433.629063] ACPI Debug: "UCEV"
[ 2433.697112] ACPI Debug: "UBTC._DSM(2)"
[ 2433.802857] evmisc-0132 ev_queue_notify_reques: Dispatching Notify on [UBTC] (Device) Value 0x80 (Status Change) Node 00000000c4abd855
[ 2433.805345] ACPI Debug: "UCEV"
[ 2433.893565] ACPI Debug: "UBTC._DSM(2)"

[Robin Labadie (lrob)]

Reproduced on Fedora as well on an LG Gram 16Z90Q. So the issue is wider than Ubuntu.
Also, for me this happens when charging with the included USBC charger; and it appears to stop once fully charged.

[Patryk (pakin157)]

Problem reproduced on Fedora 37. When charged to full, it's not spamming ACPI Errors anymore. Same hardware as OP.

[Robin Labadie (lrob)]

Issue re-reproduced on Ubuntu 22.04 as well, same laptop model (LG Gram 16Z90Q).

[Kai-Heng Feng (kaihengfeng)]

Does this issue happen when lg-laptop module is blacklisted?

[Naitik Shah (naitik)]

I have the same issue and can confirm blacklisting `lg-laptop` does not fix the issue.

[Cristian Cocos (benjaminbreeg)]

Confirmed on Ubuntu 22.10, same LG Gram computer (17Z90Q).

Edit: here is a way to stop the syslog flood: sudo rmmod int3403_thermal (https://www.reddit.com/r/linuxhardware/comments/x97m6l/comment/j2r7irr/?utm_source=reddit&utm_medium=web2x&context=3)

Note that this might be just a palliative move.

[Unix Usr (unixusr)]

I can confirm that the overheating issue happens on a LG Gram 14 14ZB90Q with an i7 1260P whenever I plug it into its power adapter. Also when rebooting I get "Failed to start Detect the available GPUs and deal with any system changes." message and have to power off before powering it back on to boot it correctly. I also get the spam of ACPI messages "ACPI Error: Aborting method \_SB.PC00.LPCB.LGEC.SEN2._TMP"

If I power it off, and leave it off for a bit, then power up just on battery the temps seem normal. But when plugging into the power adapter, it will act normal for a couple minutes, then suddenly it gets really hot, even though cpu usage is minimal, and clock speeds are low. Each core goes up to the limit around 90C.

Edit:
Forgot to mention I'm on Ubuntu 22.04 LTS, and this happens whether I user kernel 5.15.0-58 or 5.19.0-28

[Daniel Stevens (dan.r.stevens)]

I've also noticed high CPU usage on an LG Gram 17Z90Q, with a Core i7-1260P CPU, when plugging in the USB-C charger.

I checked on the CPU usage using `top`. If I unplug the charger, the kworker processes causing the CPU usage disappear within about 2 seconds, and about 10 seconds later the system will have cooled enough for the fan to start spinning down. If I plug the charger back in, the kworker processes reappear almost instantly, and about 15 seconds later the fan starts to spin up again. For me, the kworker processes and fan noise remain even when the battery is at 100% charge, so long as it remains plugged in.

A few of the kworker process commands taking up the most CPU (when plugged in):
kworker/u32:15+USBC000:00-con0
kworker/0:1+kacpi_notify
kworker/u32:2-events_power_efficient
kworker/0:0-events
kworker/1:2+kec_query
kworker/0:3-events
kworker/15:2-events

The system runs fine on battery, remaining cool and quiet.

[Kai-Heng Feng (kaihengfeng)]

Please give latest mainline kernel a try:
https://kernel.ubuntu.com/~kernel-ppa/mainline/v6.2/amd64/

[Michal C (michal1024)]

I am running LG Gram 16Z90Q (Intel I5) with PopOS and kernel 6.0.6 and I
don't have this issue. Battery lasts half a day, it does not get hot
whether plugged in or not. I had stability issues with Ubuntu, although I
was running the newest release, not the LTS version and I did not have much
time to dig into what is causing it. Then I figured System76 guys are
building OS for laptops so maybe they already did the necessary tricks. And
I fell in love with their tiling windows manager.
The only things that do not work are fingerprint reader and the screen
brightness buttons (they work with huge lag).

śr., 22 lut 2023 o 01:55 Kai-Heng Feng <email address hidden>
napisał(a):

> Please give latest mainline kernel a try:
> https://kernel.ubuntu.com/~kernel-ppa/mainline/v6.2/amd64/
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1987829
>
> Title:
> LG Gram 12gen high CPU use when USB-C/TB is in use
>
> Status in linux package in Ubuntu:
> Confirmed
> Status in linux package in Fedora:
> New
>
> Bug description:
> LG Gram laptop 17Z90Q with a Core i7-1260P CPU.
>
> Whenever an external monitor is connected to USB-C/Thunderbolt 4,
> average load goes above 3.0 and the machine is getting very hot.
>
> Output from top -H shows a lot of kworker CPU usage:
>
> top - 11:45:06 up 33 min, 2 users, load average: 3,30, 3,08, 2,79
> Threads: 1442 total, 2 running, 1440 sleeping, 0 stopped, 0 zombie
> %Cpu(s): 0,1 us, 3,7 sy, 0,0 ni, 96,1 id, 0,0 wa, 0,0 hi, 0,1 si,
> 0,0 st
> MiB Mem : 15684,6 total, 8510,2 free, 2580,8 used, 4593,6
> buff/cache
> MiB Swap: 3815,0 total, 3815,0 free, 0,0 used. 11326,9 avail
> Mem
>
> PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+
> WCHAN COMMAND
> 7766 root 20 0 0 0 0 R 19,8 0,0 0:56.05
> worker_th+ kworker/0:2-events
> 196 root 20 0 0 0 0 D 15,8 0,0 1:18.12
> ec_guard kworker/u32:2+USBC000:00-con0
> 10237 root 20 0 0 0 0 I 12,9 0,0 0:26.44
> worker_th+ kworker/0:0-events
> 1027 root 20 0 0 0 0 I 6,6 0,0 0:43.30
> worker_th+ kworker/1:3-events
> 10971 root 20 0 0 0 0 I 4,0 0,0 0:00.20
> worker_th+ kworker/15:0-events
> 175 root 20 0 0 0 0 I 2,3 0,0 0:03.24
> worker_th+ kworker/11:1-events
> 2410 root 20 0 0 0 0 I 1,7 0,0 0:05.49
> worker_th+ kworker/9:3-events
>
> Perf shows a lot of time spent inside
> handle_irq_event/acpi_ev_gpe_detect/acpi_hw_gpe_read.
>
> Additionally, kernel log is getting spammed with these lines every 4
> seconds (but also without any USB-C device attached):
>
> [ 223.514304] ACPI Error: No handler for Region [XIN1]
> (00000000f2ad4f1f) [UserDefinedRegion] (20210730/evregion-130)
> [ 223.514323] ACPI Error: Region UserDefinedRegion (ID=143) has no
> handler (20210730/exfldio-261)
>
> [ 223.514337]
> Initialized Local Variables for Method [_TMP]:
> [ 223.514339] Loc...

[Robin Labadie (lrob)]

@kaihengfeng
I gave latest mainline a try on my Fedora, installed through copr according to this doc: https://fedoraproject.org/wiki/Kernel_Vanilla_Repositories
It's kernel 6.3 instead of 6.2, but I would assume it contains changes from 6.2.
No luck, still same symptoms.

# uname -a
Linux lrob.local 6.3.0-0.rc0.20230222gt5b7c4cab.201.vanilla.fc37.x86_64 #1 SMP PREEMPT_DYNAMIC Wed Feb 22 05:16:05 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux

At idle:
# cat /proc/loadavg
2.66 3.05 2.87 3/2147 27819

Processes on top of CPU utilization:
1044 root 20 0 0 0 0 D 18.2 0.0 0:07.52 [kworker/u32:8+USBC000:00-con0]
19136 root 20 0 0 0 0 D 17.5 0.0 0:02.22 [kworker/0:0+events]
230 root 20 0 0 0 0 R 15.2 0.0 1:04.60 [kworker/0:3+kacpi_notify]

Also the issue is now occurring even when the laptop's battery is 100% charged as it is currently.
On a side note, a Thunderbolt docking station from Dell, which also charges the laptop, shows the exact same symptoms as the embedded charger.

All the best.

[Cristian Cocos (benjaminbreeg)]

Confirm this bug in Clear Linux as well.

[Kai-Heng Feng (kaihengfeng)]

Does rebooting from Windows (comment #5) temporarily fixes the issue for everyone?

[Robin Labadie (lrob)]

I would gladly answer #20 @kaihengfeng but I don't have nor want Windows on this professional machine used for sysadmin work.

Since this appears to be a global kernel issue and I didn't find it on the Linux kernel Bugzilla, I have forwarded the issue:
https://bugzilla.kernel.org/show_bug.cgi?id=217076
I'm unsure if this is necessary, but if not, there isn't much harm, and if necessary, well now it's done.

All the best

[Kitserve (ubuntu-kitserve)]

I'm experiencing this problem on an LG 14ZD90Q with Ubuntu 22.10, latest packages and kernel from the default repos. Mostly the problem occurs when the charger is plugged in, but today it also happened for a while when I had no USB-C devices connected. (I was using a couple of USB-A devices, a keyboard and mouse.) I found a mitigation: disable Intel Turbo Boost, per https://www.tautvidas.com/blog/2011/04/disabling-intel-turbo-boost/ (tl;dr: echo 1 > /sys/devices/system/cpu/intel_pstate/no_turbo as root.) It's not a fix, the CPU still keeps maxing out for no reason, but at least it doesn't overheat or max out the fan anymore. Might be useful while we wait for a kernel fix that stops this triggering in the first place.

[Pixel (madebypixel02)]

Hello everyone,

I have been following this thread for a while now, but have not yet seen others report the same thing I am experiencing. I am using an LG Gram 14Z90Q-G.AA76B and have experienced high CPU usage from kworker threads on every distro I have tried (Fedora, ArchLinux, VanillaOS, Ubuntu). From my experience, there is a somewhat reliable way to temporarily stop the high CPU usage. I don't dualboot windows, so I cannot test the suggestion of booting from windows to linux. Rather, I have noticed the following pattern:

1. Plug In USB-C cable (charging/HDMI)
2. Run "top" to verify that 3 kworker threads appear with high CPU usage. The fan will eventually kick in
3. Suspend the laptop (close the lid, press power button, press Fn+s, or manually suspend) and wait for the fan to completely turn off. Optionally unplug and plug in USB-C cable (sometimes helps).
4. Wake device from sleep.
5. Run "top" again, kworkers will be gone

Now this does not work 100% of the time, as sometimes after waking from sleep the device still keeps the kworker threads up and running, but eventually after doing this they disappear until the next reboot. This workaround gets the job done for me, as long as I don't have to reboot often.

Will share these findings on the bugzilla site as well.

Hope it helps

[eduardo furtado (pinkfromthefuture)]

Can confirm the issue on my LG Gram 17Z90Q-K (2022 model) running Manjaro (Arch) with Kernels:
6.4.2-3 (latest version I have available on my system)
6.1.38-1 (LTS)

Happens both connected to my Thunderbolt 3 dock that also charges the computer, or to the power supply. Doesn't happen when running on battery power.

Doesn't happen on my LG gram from 2021.

1. I didn't find any reports of this issue for the 2023 models. Did anyone?

I believe that we need either a Linux Kernel patch or a BIOS update, but there doesn't seem to be any updates to the BIOS of the 2022 lined up of LG Gram.

2. How can we get this fixed? Who can save us!?

3. Are there any workarounds that can be programmatically applied?
Someone here: https://bugzilla.kernel.org/show_bug.cgi?id=217076#c7
suggests setting the kernel parameter acpi_mask_gpe=0x6E
But I'm resistant to try it because:

```
When you specify a kernel boot parameter like acpi_mask_gpe=0x6E, you're telling the kernel to ignore or mask a specific ACPI GPE, in this case, the GPE with the address 0x6E.

This can be useful in certain scenarios where a specific GPE is causing issues, like system instability or high CPU usage. By masking the GPE, you prevent the system from processing that event, which can work around the issue.

However, you should only use this parameter if you are sure that the specific GPE is causing issues and you understand the implications of masking it. In some cases, it can lead to other problems, like certain hardware events not being correctly detected by the OS.
``` - Chat GPT 4

[eduardo furtado (pinkfromthefuture)]

Here is my elegant workaround to the problem:
```
[Unit]
Description=Fixes many issues with the 2022 LG Grams running linux and sets charging limit to 80

# save this script to /etc/systemd/system/lg-gram.service
# then run:
# sudo systemctl daemon-reload
# sudo systemctl enable lg-gram.service
# sudo systemctl start lg-gram.service

# more documentation: https://www.reddit.com/r/LGgram/comments/150p3rg/critical_bug_affecting_the_2022_lineup_on_linux/

[Service]
Type=oneshot
# Unmask GPE interrupts to resolve the issue of high temperatures and fan noise even on idle when the laptop is charging through USB-C/TB:
ExecStart=/bin/bash -c "echo 'unmask' > /sys/firmware/acpi/interrupts/gpe6E"

# sets charging limit to 80 to increase battery longevity:
ExecStart=/bin/bash -c "echo 80 > /sys/class/power_supply/CMB0/charge_control_end_threshold"

# Disable "Silent mode":
ExecStart=/bin/bash -c "echo 1 > /sys/devices/platform/lg-laptop/fan_mode"

# Unload the int3403 temp sensor library from the kernel to fix ACPI flood issue:
# ExecStart=/bin/sh -c "rmmod int3403_thermal"

# Disable turbo boost (trade single threaded performance for lower heat output and maybe battery life)
# ExecStart=/bin/sh -c 'echo 1 > /sys/devices/system/cpu/intel_pstate/no_turbo'
# ExecStop=/bin/sh -c 'echo 0 > /sys/devices/system/cpu/intel_pstate/no_turbo'

# Fix for thermal throttle issue that on some distros can put the CPU running on low wattages:
# ExecStart=/bin/bash -c "systemctl disable --now thermald"

RemainAfterExit=yes

[Install]
WantedBy=multi-user.target

```

--
The issue seems to be caused by:
```some miscommunication between Linux thinking it can probe for thermal info on a device which did not register a handler to do so```
Source - https://www.reddit.com/r/linuxhardware/comments/x97m6l/fedora_lg_gram_16_2022_12th_gen_alder_lake/ (added to the original post)

I'm happy to confirm that the kernel parameter acpi_mask_gpe=0x6E seems to fix the issue of fans blasting and high temperatures even on idle!
An observed drawback from this solution is that is breaks the functionality of the screen brighness buttons: it still works, but you can hold it, and it also has a big delay in applying each setting - This doesn't bother me as I already use some scripts with a custom keyboard shortcut to set the brighness of all my displays at once. Another solution is unmasking the GPE interrupts not through a kernel parameter, but after boot with: echo unmask > /sys/firmware/acpi/interrupts/gpe6E - This way the brightness button issues don't manifest.
Furthermore, setting the kernel parameter acpi_mask_gpe=0x6E, it could be affecting idle power draws if the values returned by GPE are used to put cpus into idle states. Thankfully the issue only happens when the laptops are charging, so it wouldn't kill battery life.
From the kernel documentation I could find:
acpi_mask_gpe= [HW,ACPI]Due to the existence of _Lxx/_Exx, some GPEs triggeredby unsupported hardware/firmware features can result inGPE floodings that cannot be automatically disabled bythe GPE dispatcher.This facility can be used to prevent such uncontrolledGPE floodings.Format: <byte> or <bitmap-list>
So the documentation i...

[paulo vieira (paulosantosvieira)]

I'm also experiencing this on a LG 17Z90Q (on Ubuntu 22.04 and Mint 21.2)

Two hacky ways to "solve" the problem (as described in the previous posts):

1) suspend the computer and wake
2) remove the usb-c charging cable and plug again

But this doesn't seem to always. Sometimes works, sometimes not.

[eduardo furtado (pinkfromthefuture)]

Paulo, the proper solution is also described in this thread. Looks like you didn't read all before posting

[Chris Bertin (chris-bertin)]

This problem is a real nightmare. Basically, a LG-gram is unusable when the power cable is connected. A while back, the issue would only happen when an SD card was plugged in. I got into the habit of removing my backup card. Now, it happens w/ or w/out the SD card. There is another bug report filed, but it is not getting addressed either:

https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1990876