4

AC-adapter unplugged:

$ echo power | sudo tee energy_performance_preference
power
$ echo $?
0

AC-adapter plugged-in:

$ echo power | sudo tee energy_performance_preference
power
tee: energy_performance_preference: Device or resource busy

Yes, I have intel p-states HWP-capable CPU, otherwise i wouldn't have that setting above.

My laptop is running Gentoo Linux hardened with 5.17.4-gentoo-x86_64 kernel.

Maybe it's somehow related, but /var/log/syslog shows that after unplugging adapter:

May 27 17:19:27 mathroom laptop-mode: enabled, active
May 27 17:19:27 mathroom rfkill: block set for type bluetooth
May 27 17:19:27 mathroom laptop-mode: LCD Brightness Command succeeded.
May 27 17:19:27 mathroom kernel: EXT4-fs (sda3): re-mounted. Quota mode: disabled.
May 27 17:19:27 mathroom kernel: EXT4-fs (sda4): re-mounted. Quota mode: disabled.
May 27 17:19:27 mathroom kernel: r8169 0000:02:00.0 enp2s0: Link is Down
May 27 17:19:28 mathroom root: ACPI event unhandled: battery PNP0C0A:00 00000080 00000001
May 27 17:19:28 mathroom root: ACPI event unhandled: battery PNP0C0A:00 00000081 00000001
May 27 17:19:28 mathroom root: ACPI event unhandled: battery PNP0C0A:00 00000080 00000001
May 27 17:19:28 mathroom root: ACPI event unhandled: battery PNP0C0A:00 00000001 00000001

, and this after plugging it back in:

May 27 17:20:36 mathroom laptop-mode: enabled, active
May 27 17:20:36 mathroom rfkill: unblock set for type bluetooth
May 27 17:20:36 mathroom laptop-mode: LCD Brightness Command succeeded.
May 27 17:20:36 mathroom kernel: NMI watchdog: Enabled. Permanently consumes one hw-PMU counter.
May 27 17:20:36 mathroom kernel: EXT4-fs (sda3): re-mounted. Quota mode: disabled.
May 27 17:20:36 mathroom kernel: EXT4-fs (sda4): re-mounted. Quota mode: disabled.
May 27 17:20:36 mathroom kernel: r8169 0000:02:00.0 enp2s0: Link is Down
May 27 17:20:36 mathroom root: ACPI event unhandled: battery PNP0C0A:00 00000080 00000001
May 27 17:20:36 mathroom root: ACPI event unhandled: ac_adapter ACPI0003:00 00000080 00000001
May 27 17:20:37 mathroom root: ACPI event unhandled: battery PNP0C0A:00 00000081 00000001
May 27 17:20:37 mathroom root: ACPI event unhandled: battery PNP0C0A:00 00000080 00000001
May 27 17:20:37 mathroom root: ACPI event unhandled: battery PNP0C0A:00 00000001 00000001

Also, there's no diff-erence in /etc/mtab before and after changing adapter state.

It's worth noting that at the time ac-adapter IS connected, i CAN write to scaling_governor, for example, but not to energy_performance_preference.

This post didn't help me(lsof +D /sys output is unrelated).

Any help will be appreciated.

mathway
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  • 3

1 Answers1

2

What is the output of the following commands (I know this question would better fit into to a comment but I don't have enough reputation yet):

$ cat /sys/devices/system/cpu/cpufreq/*/energy_performance_available_preferences  
$ cat /sys/devices/system/cpu/cpufreq/*/scaling_governor

On my Arch Linux with amd_pstate_epp when my scaling_governor is set to performance I can only select performance as EPP preference (energy_performance_available_preferences also only contains performance then). When I then try to select an unavailable EPP preference I get the Device or resource busy error. Maybe plugging in your AC-adapter changes your governor setting?

$ uname -a
Linux some-hostname 6.7.4-arch1-1 #1 SMP PREEMPT_DYNAMIC Mon, 05 Feb 2024 22:07:49 +0000 x86_64 GNU/Linux
$ cd /sys/devices/system/cpu/cpufreq/policy0/
$ echo powersave | sudo tee scaling_governor
powersave
$ cat energy_performance_available_preferences
default performance balance_performance balance_power power
$ echo power | sudo tee energy_performance_preference 
power
$ echo performance | sudo tee scaling_governor
performance
$ cat energy_performance_available_preferences       
performance
$ echo power | sudo tee energy_performance_preference
power
tee: energy_performance_preference: Device or resource busy

The exact reason for this, however, is beyond my knowledge.

Kippi
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