[REGRESSION] bitland-mifs-wmi: power-saver write is accepted but profile remains balanced on Redmi Book Pro 14 2022

To: Mingyou Chen <[email protected]>, Hans de Goede 
<[email protected]>, Ilpo Järvinen <[email protected]>
Cc: [email protected], [email protected]
Subject: [REGRESSION] bitland-mifs-wmi: power-saver write is accepted 
but profile remains balanced on Redmi Book Pro 14 2022

Hello,

Linux 7.1's new bitland-mifs-wmi driver binds on my TIMI Redmi Book Pro 
14 2022 (TM2107) and exposes platform profiles, but selecting 
power-saver is silently ineffective. The userspace request returns 
success while the sysfs profile never leaves "balanced".

This reproduces without KDE:

     $ cat /sys/class/platform-profile/platform-profile-0/name
     bitland-mifs-wmi

     $ cat /sys/firmware/acpi/platform_profile_choices
     low-power balanced balanced-performance performance

     $ cat /sys/firmware/acpi/platform_profile
     balanced

     $ powerprofilesctl set power-saver
     $ echo $?
     0

     $ powerprofilesctl get
     balanced

     $ cat /sys/firmware/acpi/platform_profile
     balanced

     $ cat 
/sys/devices/system/cpu/cpufreq/policy0/energy_performance_preference
     balance_performance

I repeated the request while polling platform_profile every 50 ms. The 
only observed value was "balanced"; no transient "low-power" state 
appeared. The request completed in 162 ms with exit status 0. 
power-profiles-daemon also persisted Profile=balanced afterward. There 
were no relevant kernel or daemon log messages.

Expected result:

The advertised low-power profile is selected, platform_profile reads 
"low-power", and the AMD P-State EPP becomes power-oriented.

Actual result:

The operation reports success, but firmware, power-profiles-daemon, and 
all AMD CPU policies remain balanced.

System information:

     Distribution: CachyOS
     Kernel: 7.1.3-2-cachyos
     DMI vendor/product/board: TIMI / Redmi Book Pro 14 2022 / TM2107
     BIOS: TIMI RMARB4B0P1010, 2023-06-28
     CPU: AMD Ryzen 5 6600H with Radeon Graphics
     bitland_mifs_wmi srcversion: 0C0A58A1AE25437010C0B5E
     power-profiles-daemon: 0.30-3
     Power source during reproduction: AC online
     Active profile holds: none
     Other power managers (TLP, TuneD, auto-cpufreq): none

powerprofilesctl identifies both drivers:

     power-saver:
       CpuDriver: amd_pstate
       PlatformDriver: platform_profile

The kernel taint value is 512 because of an unrelated AMDGPU display 
warning during boot (dcn31_program_compbuf_size); bitland_mifs_wmi 
itself is not tainted and emitted no warning during reproduction.

This began after the 2026-06-24 update from Linux 7.0.12 to 7.1.1, which 
introduced bitland-mifs-wmi (dc1ec4fa86b2). Power Saver worked before 
that update. My installed 6.18 LTS kernel does not contain this driver, 
but I have not yet performed an LTS or vanilla-mainline A/B test, so I 
am explicitly reporting this as reproduced on a CachyOS kernel.


Regards,
Robert

Assisted-by: OpenAI Codex:GPT-5

Robert Munro
Director, Executive Team
[email protected] <mailto:[email protected]>
ethicsbowl.ca <https://ethicsbowl.ca>
Ethics Bowl Canada