[SOLVED] [linux-lts 6.18.57] Power button dead / PWRF missing

jorgecg · 2026-10-17 21:29:54

After upgrading linux-lts 6.18.56-1 -> 6.18.57-1 the physical power button does nothing. KDE Plasma was also upgraded 6.7.5 -> 6.8.0 the same day, but the difference shows up in the kernel log at boot, so it does not look userspace-related.

Hardware: Timi (Xiaomi) TM1701, Intel Core i5-8250U, BIOS XMAKB5R0P0401

Same machine, same kernel command line in both cases:

BOOT_IMAGE=/vmlinuz-linux-lts root=UUID=... rw rootflags=subvol=@ loglevel=3 quiet pcie_aspm=off

6.18.54-1-lts and 6.18.56-1-lts, dmesg:

ACPI: button: Power Button [PWRB]
ACPI: button: Power Button [PWRF]

6.18.57-1-lts, dmesg only shows:

ACPI: button: Power Button [PWRB]

and each time I press the button:

ACPI Error: No installed handler for fixed event - PowerButton (2), disabling (20250807/evevent-255)

With 6.18.57, evtest on /dev/input/event0 (Power Button) shows no events and logind logs nothing. The firmware raises the fixed event, but nothing handles it. systemctl suspend / poweroff still work, and PowerDevil triggers fine when I invoke the action over D-Bus.

I could not confirm the cause. Upstream reworked how fixed event buttons are registered in the 6.19 cycle (platform devices, drivers no longer bound to fixed buttons), so a partial backport to 6.18.y might explain it.

Is anyone else seeing this with 6.18.57 (or a newer linux-lts)? Happy to provide the full dmesg or acpidump.

Last edited by jorgecg (2026-10-18 10:30:00)

seth · 2026-10-17 21:49:17

Backported for sure, https://github.com/gregkh/linux/commits … ivers/acpi - did you test the behavior of the main kernel?

KDE Plasma was also upgraded 6.7.5 -> 6.8.0 the same day, but

Other keys (shortcuts) work?

(unlikely) x-ref, https://bbs.archlinux.org/viewtopic.php?id=315237

jorgecg · 2026-10-17 22:24:11

Tested with the main kernel (linux 7.x) and the power button works perfectly now, suspending the system as expected.

Prior to testing the main kernel, I also verified other shortcuts and hardware controls on 6.18.57-lts:

Lid switch (LID0): Closing the lid locks the screen and prompts for password as expected.

Fn keys: Volume up/down/mute and display brightness controls work without issues.

Plasma shortcuts: Global desktop shortcuts are fully functional.

This confirms that KDE Plasma 6.8.0 and the overall event pipeline are working fine, and the issue is strictly isolated to an incomplete stable backport in linux-lts 6.18.57.

For context, the 6.18.57 history of drivers/acpi/scan.c (Oct 15) has only two new commits:

"ACPI: scan: Do not mark button ACPI devices as wakeup-capable"

"ACPI: scan: Use acpi_setup_gpe_for_wake() for buttons"

Missing from it are "ACPI: scan: Register platform devices for fixed event buttons" and "ACPI: scan: Do not bind ACPI drivers to fixed event buttons", which are part of the same upstream series. Since "ACPI: button: Convert the driver to a platform one" is present in 6.18.57, fixed event buttons (PWRF) have nothing left to bind to.

Leaving these details here in case someone wants to forward this upstream or notify the kernel stable maintainers.

Thanks for the help, Seth!

seth · 2026-10-18 07:29:38

https://lore.kernel.org/stable/5fe757e7 … 9@stwm.de/

jorgecg · 2026-10-18 10:28:23

Thanks for the link and your time, Seth!

I see the kernel maintainers are already aware of the issue, so if a moderator could close this thread that would be great.

Cheers!

Arch Linux

#1 2026-10-17 21:29:54

[SOLVED] [linux-lts 6.18.57] Power button dead / PWRF missing

#2 2026-10-17 21:49:17

Re: [SOLVED] [linux-lts 6.18.57] Power button dead / PWRF missing

#3 2026-10-17 22:24:11

Re: [SOLVED] [linux-lts 6.18.57] Power button dead / PWRF missing

#4 2026-10-18 07:29:38

Re: [SOLVED] [linux-lts 6.18.57] Power button dead / PWRF missing

#5 2026-10-18 10:28:23

Re: [SOLVED] [linux-lts 6.18.57] Power button dead / PWRF missing

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