[BUG] [Keyboard Backlight] Auto-mode (timeout) not working - Lenovo Yoga 9 2in1 14ILL10 Aura Edition

[ID-1010]

Pre-flight checklist

• I have searched existing issues and this is not a duplicate.
• I have read the Contributing Guidelines.
• I have verified the issue is reproducible with the latest available CachyOS kernel.
• I have tried to reproduce the issue on Arch Linux's linux kernel.

Upstream / vanilla kernel check

I tested with a vanilla/upstream kernel and the issue ALSO reproduces there (upstream bug — please report upstream)

Kernel variant

linux-cachyos-rc

System information (cachyos-bugreport.sh)

https://paste.cachyos.org/p/cfa3f89.log

Manual system information (if cachyos-bugreport.sh is unavailable)

System:
  Kernel: 7.0.0-rc7-1-cachyos-rc arch: x86_64 bits: 64 compiler: clang
    v: 22.1.2 clocksource: tsc avail: acpi_pm
    parameters: initrd=\initramfs-linux-cachyos-rc.img
    root=UUID=5a67c41e-0ef7-4f8c-8e5b-a67990cebf26 rw rootflags=subvol=/@
    zswap.enabled=0 nowatchdog quiet splash
  Desktop: KDE Plasma v: 6.6.3 tk: Qt v: N/A info: frameworks v: 6.24.0
    wm: kwin_wayland vt: 2 dm: SDDM Distro: CachyOS base: Arch Linux
Machine:
  Type: Convertible System: LENOVO product: 83LC v: Yoga 9 2-in-1 14ILL10
    serial: <superuser required> Chassis: type: 31 v: Yoga 9 2-in-1 14ILL10
    serial: <superuser required>
  Mobo: LENOVO model: LNVNB161216 v: SDK0T76574 WIN
    serial: <superuser required> part-nu: LENOVO_MT_83LC_BU_idea_FM_Yoga 9
    2-in-1 14ILL10 uuid: <superuser required> Firmware: UEFI vendor: LENOVO
    v: Q9CN29WW date: 12/02/2025
Battery:
  ID-1: BAT0 charge: 68 Wh (89.5%) condition: 75.9/75 Wh (101.2%) volts: 8.44
    min: 7.7 model: ATL L24N4PH2 type: Li-poly serial: <filter> charging:
    status: not charging type: long_life avail: fast,long_life,standard
    cycles: 3
CPU:
  Info: model: Intel Core Ultra 7 258V bits: 64 type: MCP arch: Lunar Lake
    level: v3 note: check built: 2024+ process: TSMC n3b (3nm) family: 6
    model-id: 0xBD (189) stepping: 1 microcode: 0x125
  Topology: cpus: 1x dies: 1 clusters: 5 cores: 8 smt: <unsupported> cache:
    L1: 832 KiB desc: d-4x32 KiB, 4x48 KiB; i-8x64 KiB L2: 14 MiB
    desc: 4x2.5 MiB, 1x4 MiB L3: 12 MiB desc: 1x12 MiB
  Speed (MHz): avg: 1251 min/max: 400/4700:4800:3700 scaling:
    driver: intel_pstate governor: powersave cores: 1: 1251 2: 1251 3: 1251
    4: 1251 5: 1251 6: 1251 7: 1251 8: 1251 bogomips: 52838
  Flags-basic: avx avx2 ht lm nx pae sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx
  Vulnerabilities:
  Type: gather_data_sampling status: Not affected
  Type: ghostwrite status: Not affected
  Type: indirect_target_selection status: Not affected
  Type: itlb_multihit status: Not affected
  Type: l1tf status: Not affected
  Type: mds status: Not affected
  Type: meltdown status: Not affected
  Type: mmio_stale_data status: Not affected
  Type: old_microcode status: Not affected
  Type: reg_file_data_sampling status: Not affected
  Type: retbleed status: Not affected
  Type: spec_rstack_overflow status: Not affected
  Type: spec_store_bypass mitigation: Speculative Store Bypass disabled via
    prctl
  Type: spectre_v1 mitigation: usercopy/swapgs barriers and __user pointer
    sanitization
  Type: spectre_v2 mitigation: Enhanced / Automatic IBRS; IBPB: conditional;
    PBRSB-eIBRS: Not affected; BHI: BHI_DIS_S
  Type: srbds status: Not affected
  Type: tsa status: Not affected
  Type: tsx_async_abort status: Not affected
  Type: vmscape mitigation: IBPB before exit to userspace
Graphics:
  Device-1: Intel Lunar Lake [Intel Arc Graphics 130V / 140V] vendor: Lenovo
    driver: xe v: kernel arch: Xe2 process: TSMC n3 (3nm) built: 2024+ ports:
    active: eDP-1 empty: DP-1,DP-2,DP-3 bus-ID: 00:02.0 chip-ID: 8086:64a0
    class-ID: 0300
  Device-2: Luxvisions Innotech Integrated Camera
    driver: hid-sensor-hub,usbhid,uvcvideo type: USB rev: 2.0 speed: 480 Mb/s
    lanes: 1 mode: 2.0 bus-ID: 3-4:2 chip-ID: 30c9:00f7 class-ID: fe01
    serial: <filter>
  Display: wayland server: X.org v: 1.21.1.21 with: Xwayland v: 24.1.9
    compositor: kwin_wayland driver: gpu: xe display-ID: 0
  Monitor-1: eDP-1 model: Samsung ATNA40HQ01-0 built: 2024 res:
    mode: 2880x1800 hz: 120 scale: 160% (1.6) to: 1800x1125 dpi: 244 gamma: 1.2
    size: 300x190mm (11.81x7.48") diag: 355mm (13.98") modes: 2880x1800
  API: EGL v: 1.5 hw: drv: intel iris platforms: device: 0 drv: iris
    device: 1 drv: swrast gbm: drv: iris surfaceless: drv: iris wayland:
    drv: iris x11: drv: iris
  API: OpenGL v: 4.6 compat-v: 4.5 vendor: intel mesa v: 26.0.4-arch2.2
    glx-v: 1.4 direct-render: yes renderer: Mesa Intel Graphics (LNL)
    device-ID: 8086:64a0 memory: 30.13 GiB unified: yes display-ID: :0.0
  API: Vulkan v: 1.4.341 layers: 2 device: 0 type: integrated-gpu
    name: Intel Graphics (LNL) driver: mesa intel v: 26.0.4-arch2.2
    device-ID: 8086:64a0 surfaces: N/A
  Info: Tools: api: clinfo, eglinfo, glxinfo, vulkaninfo
    de: kscreen-console,kscreen-doctor gpu: corectrl wl: wayland-info
    x11: xdpyinfo, xprop, xrandr
Audio:
  Device-1: Intel Lunar Lake-M HD Audio vendor: Lenovo
    driver: sof-audio-pci-intel-lnl
    alternate: snd_sof_pci_intel_lnl,snd_hda_intel bus-ID: 00:1f.3
    chip-ID: 8086:a828 class-ID: 0401
  API: ALSA v: k7.0.0-rc7-1-cachyos-rc status: kernel-api
    tools: alsactl,alsamixer,amixer
  Server-1: sndiod v: N/A status: off tools: aucat,midicat,sndioctl
  Server-2: JACK v: 0.126.0 status: off tools: N/A
  Server-3: PipeWire v: 1.6.2 status: active with: 1: pipewire-pulse
    status: active 2: wireplumber status: active 3: pipewire-alsa type: plugin
    tools: pactl,pw-cat,pw-cli,wpctl
Network:
  Device-1: Intel BE201 320MHz driver: iwlwifi v: kernel port: N/A
    bus-ID: 00:14.3 chip-ID: 8086:a840 class-ID: 0280
  IF: wlan0 state: up mac: <filter>
  IF-ID-1: tun0 state: unknown speed: 10000 Mbps duplex: full mac: N/A
  Info: services: NetworkManager, systemd-timesyncd, wpa_supplicant
Bluetooth:
  Device-1: Intel driver: btintel_pcie v: 0.1 bus-ID: 00:14.7
    chip-ID: 8086:a876 class-ID: 0d11
  Report: btmgmt ID: hci0 rfk-id: 2 state: up address: <filter> bt-v: 5.4
    lmp-v: 13 status: discoverable: no pairing: no class-ID: 7c0000
Drives:
  Local Storage: total: 953.87 GiB used: 218.35 GiB (22.9%)
  SMART Message: Unable to run smartctl. Root privileges required.
  ID-1: /dev/nvme0n1 maj-min: 259:0 vendor: Western Digital model: WD PC
    SN7100S SDFPMSL-1T00-1101 size: 953.87 GiB block-size: physical: 512 B
    logical: 512 B speed: 63.2 Gb/s lanes: 4 tech: SSD serial: <filter>
    fw-rev: 7611M001 temp: 27.9 C scheme: GPT
Partition:
  ID-1: / raw-size: 951.87 GiB size: 951.87 GiB (100.00%)
    used: 218.11 GiB (22.9%) fs: btrfs dev: /dev/nvme0n1p2 maj-min: 259:2
  ID-2: /boot raw-size: 2 GiB size: 2 GiB (99.80%) used: 248.4 MiB (12.2%)
    fs: vfat dev: /dev/nvme0n1p1 maj-min: 259:1
  ID-3: /home raw-size: 951.87 GiB size: 951.87 GiB (100.00%)
    used: 218.11 GiB (22.9%) fs: btrfs dev: /dev/nvme0n1p2 maj-min: 259:2
  ID-4: /var/log raw-size: 951.87 GiB size: 951.87 GiB (100.00%)
    used: 218.11 GiB (22.9%) fs: btrfs dev: /dev/nvme0n1p2 maj-min: 259:2
  ID-5: /var/tmp raw-size: 951.87 GiB size: 951.87 GiB (100.00%)
    used: 218.11 GiB (22.9%) fs: btrfs dev: /dev/nvme0n1p2 maj-min: 259:2
Swap:
  Kernel: swappiness: 150 (default 60) cache-pressure: 50 (default 100)
    zswap: no
  ID-1: swap-1 type: zram size: 30.85 GiB used: 0 KiB (0.0%) priority: 100
    comp: zstd avail: lzo-rle,lzo,lz4,lz4hc,deflate,842 dev: /dev/zram0
Sensors:
  System Temperatures: cpu: N/A mobo: N/A
  Fan Speeds (rpm): cpu: 0
Info:
  Memory: total: 32 GiB note: est. available: 30.86 GiB used: 5.03 GiB (16.3%)
  Processes: 439 Power: uptime: 52m states: freeze,mem,disk suspend: s2idle
    wakeups: 0 hibernate: platform avail: shutdown, reboot, suspend, test_resume
    image: 12.28 GiB services: org_kde_powerdevil, power-profiles-daemon,
    upowerd Init: systemd v: 260 default: graphical tool: systemctl
  Packages: pm: pacman pkgs: 1402 libs: 349 tools: octopi,paru Compilers:
    clang: 22.1.2 gcc: 15.2.1 Shell: fish v: 4.6.0 running-in: konsole
    inxi: 3.3.40

Bug description

Description

On the Lenovo Yoga 9 2in1 14ILL10 Aura Edition, the keyboard backlight hardware Auto-mode does not function correctly in Linux.

Current Behavior:

1. Manual Mode (100% brightness): Works as intended (stays on).
2. Auto Mode (Fn+Space): The backlight stays on indefinitely. It fails to auto-extinguish after the hardware-defined 10 seconds of inactivity. Pressing a key does not "wake" it because it never sleeps.

System Info:

• Model: 83LC002BCK (Aura Edition)
• CPU: Intel Core Ultra 7 258V (Lunar Lake)
• Kernel: linux-cachyos 7.0.0-rc7-1-cachyos-rc (64-bit) (also tested on latest stable Arch kernel)

Technical Info:

The device uses the VPC2004 ACPI interface.
ls /sys/class/leds/tpacpi::kbd_backlight/trigger shows [none].

It seems the ideapad_laptop driver is missing the specific ACPI event handling for the new Aura Edition's auto-timeout logic.

Steps to reproduce

Set up OS timeout: Go to System Settings -> Power Management and enable "Turn off keyboard backlight after 10s".

Switch to Auto Mode: Use the Fn + Space shortcut to cycle through the backlight modes until the "Auto" icon (with the "A" symbol) appears on the screen.

Wait for inactivity: Stop typing and do not move the mouse for at least 15-20 seconds.

Observe: Notice that the keyboard backlight remains ON (at 50% or 100% depending on ambient light), ignoring both the hardware-defined 10s timeout and the KDE Plasma software timeout.

Comparison: Switch to "Off" or "100%" (Manual) using Fn + Space to verify that the hardware cycling itself works, but the "Auto" logic is dead.

Expected behavior

When the keyboard backlight is set to "Auto" mode (via Fn+Space), I expect the following behavior:

1. The backlight should automatically adjust its brightness (50% or 100%) .
2. After approximately 10 seconds of keyboard/touchpad inactivity, the backlight should turn off completely to save power.
3. Pressing any key or touching the trackpad should instantly wake the backlight back to its previous state.
4. The KDE Plasma "Keyboard Backlight" timeout settings should be honored by the system.

Actual behavior

1. When the "Auto" mode is activated via Fn+Space, the keyboard backlight stays ON indefinitely at a fixed brightness level.
2. It completely ignores the hardware inactivity timeout (should be ~10s).
3. It also completely ignores the software-defined timeout in KDE Plasma's Power Management settings.
4. The backlight never turns off, which causes unnecessary battery drain on this Lunar Lake (Aura Edition) device.
5. Essentially, the "Auto" mode acts exactly like the "Always On / 100%" mode, making the smart features of this laptop unusable in Linux.

Logs / stack traces

-- KERNEL LOGS ---
[    5.374779] ACPI: bus type thunderbolt registered
[    5.435034] input: Lenovo Yoga Tablet Mode Control switch as /devices/platform/PNP0C14:01/wmi_bus/wmi_bus-PNP0C14:01/06129D99-6083-4164-81AD-F092F9D773A6-3/input/input7
[    5.543197] lenovo_wmi_capdata 362A3AFE-3D96-4665-8530-96DAD5BB300E-15: bound B642801B-3D21-45DE-90AE-6E86F164FB21-16 (ops lwmi_cd_sub_component_ops [lenovo_wmi_capdata])
[    5.549074] lenovo_wmi_gamezone 887B54E3-DDDC-4B2C-8B88-68A26A8835D0-11: platform_profile probe failed
[    5.750916] acpi device:2a: SDCA function SmartAmp (type 1) at 0x1
[    5.750920] acpi device:2b: SDCA function UAJ (type 6) at 0x3
[    5.750922] acpi device:2c: SDCA function HID (type 10) at 0x4
[    6.000753] ucsi_acpi USBC000:00: bogus connector number in CCI: 1
[    6.083101] ucsi_acpi USBC000:00: bogus connector number in CCI: 1
[    6.161322] ucsi_acpi USBC000:00: bogus connector number in CCI: 1
[    6.248963] ucsi_acpi USBC000:00: UCSI: Invalid num_connectors 131. Likely buggy FW
[    9.332332] input: Lenovo Yoga Bluetooth Silent Mouse Keyboard as /devices/virtual/misc/uhid/0005:17EF:6200.0005/input/input23
[    9.353176] input: Lenovo Yoga Bluetooth Silent Mouse as /devices/virtual/misc/uhid/0005:17EF:6200.0005/input/input24
[    9.353328] hid-generic 0005:17EF:6200.0005: input,hidraw4: BLUETOOTH HID v10.02 Keyboard [Lenovo Yoga Bluetooth Silent Mouse] on 9c:b1:50:fd:e0:9d
[   10.866614] cs35l56 spi-cs35l56-left: DSP1: Misc: C:\Project\Lenovo\C9X0\Lenovoprameter\C9X0_3.11.26\Posturebin\LX\init\CS35L56 [I2C - 0x60] @ DC35L56
[   10.964116] cs35l56 spi-cs35l56-right: DSP1: Misc: C:\Project\Lenovo\C9X0\Lenovoprameter\C9X0_3.11.26\Posturebin\LX\init\CS35L56 [I2C - 0x62] @ DC35L56
[  279.436497] ACPI BIOS Error (bug): Could not resolve symbol [\_SB.PC00.LPCB.EC0._Q44.WM00], AE_NOT_FOUND (20251212/psargs-332)
[  279.436532] ACPI Error: Aborting method \_SB.PC00.LPCB.EC0._Q44 due to previous error (AE_NOT_FOUND) (20251212/psparse-531)
[  280.226504] ACPI BIOS Error (bug): Could not resolve symbol [\_SB.PC00.LPCB.EC0._Q44.WM00], AE_NOT_FOUND (20251212/psargs-332)
[  280.226524] ACPI Error: Aborting method \_SB.PC00.LPCB.EC0._Q44 due to previous error (AE_NOT_FOUND) (20251212/psparse-531)

--- BACKLIGHT INFO ---
Path: lrwxrwxrwx - root  7 apr 08:08 /sys/class/leds/platform::kbd_backlight -> ../../devices/pci0000:00/0000:00:1f.0/PNP0C09:00/VPC2004:00/leds/platform::kbd_backlight
Trigger: [none] usb-gadget usb-host rc-feedback kbd-scrolllock kbd-numlock kbd-capslock kbd-kanalock kbd-shiftlock kbd-altgrlock kbd-ctrllock kbd-altlock kbd-shiftllock kbd-shiftrlock kbd-ctrlllock kbd-ctrlrlock disk-activity disk-read disk-write mtd nand-disk cpu cpu0 cpu1 cpu2 cpu3 cpu4 cpu5 cpu6 cpu7 panic ADP0-online BAT0-charging-or-full BAT0-charging BAT0-full BAT0-charging-blink-full-solid BAT0-charging-orange-full-green rfkill-any rfkill-none rfkill0 rfkill1 bluetooth-power hci0-power rfkill2 audio-mute audio-micmute phy0rx phy0tx phy0assoc phy0radio rfkill3 ucsi-source-psy-USBC000:001-online ucsi-source-psy-USBC000:002-online ucsi-source-psy-USBC000:003-online
Brightness: 0

Additional system information

inxi -Fxxxz
System:
Kernel: 7.0.0-rc7-1-cachyos-rc arch: x86_64 bits: 64 compiler: clang
v: 22.1.2 clocksource: tsc
Desktop: KDE Plasma v: 6.6.3 tk: Qt v: N/A wm: kwin_wayland vt: 2 dm: SDDM
Distro: CachyOS base: Arch Linux
Machine:
Type: Convertible System: LENOVO product: 83LC v: Yoga 9 2-in-1 14ILL10
serial: Chassis: type: 31 v: Yoga 9 2-in-1 14ILL10
serial:
Mobo: LENOVO model: LNVNB161216 v: SDK0T76574 WIN
serial: part-nu: LENOVO_MT_83LC_BU_idea_FM_Yoga 9
2-in-1 14ILL10 uuid: Firmware: UEFI vendor: LENOVO
v: Q9CN29WW date: 12/02/2025
Battery:
ID-1: BAT0 charge: 68 Wh (89.5%) condition: 75.9/75 Wh (101.2%) volts: 8.44
min: 7.7 model: ATL L24N4PH2 type: Li-poly serial: charging:
status: not charging type: long_life cycles: 3
CPU:
Info: 8-core model: Intel Core Ultra 7 258V bits: 64 type: MCP
smt: arch: Lunar Lake rev: 1 cache: L1: 832 KiB L2: 14 MiB
L3: 12 MiB
Speed (MHz): avg: 400 min/max: 400/4700:4800:3700 cores: 1: 400 2: 400
3: 400 4: 400 5: 400 6: 400 7: 400 8: 400 bogomips: 52838
Flags-basic: avx avx2 ht lm nx pae sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx
Graphics:
Device-1: Intel Lunar Lake [Intel Arc Graphics 130V / 140V] vendor: Lenovo
driver: xe v: kernel arch: Xe2 ports: active: eDP-1 empty: DP-1,DP-2,DP-3
bus-ID: 00:02.0 chip-ID: 8086:64a0 class-ID: 0300
Device-2: Luxvisions Innotech Integrated Camera
driver: hid-sensor-hub,usbhid,uvcvideo type: USB rev: 2.0 speed: 480 Mb/s
lanes: 1 bus-ID: 3-4:2 chip-ID: 30c9:00f7 class-ID: fe01 serial:
Display: wayland server: X.org v: 1.21.1.21 with: Xwayland v: 24.1.9
compositor: kwin_wayland driver: gpu: xe display-ID: 0
Monitor-1: eDP-1 model: Samsung ATNA40HQ01-0 res: mode: 2880x1800 hz: 120
scale: 160% (1.6) to: 1800x1125 dpi: 244 size: 300x190mm (11.81x7.48")
diag: 355mm (13.98") modes: 2880x1800
API: EGL v: 1.5 hw: drv: intel iris platforms: device: 0 drv: iris
device: 1 drv: swrast gbm: drv: iris surfaceless: drv: iris wayland:
drv: iris x11: drv: iris
API: OpenGL v: 4.6 compat-v: 4.5 vendor: intel mesa v: 26.0.4-arch2.2
glx-v: 1.4 direct-render: yes renderer: Mesa Intel Graphics (LNL)
device-ID: 8086:64a0 display-ID: :0.0
API: Vulkan v: 1.4.341 layers: 2 surfaces: N/A device: 0
type: integrated-gpu driver: mesa intel device-ID: 8086:64a0
Info: Tools: api: clinfo, eglinfo, glxinfo, vulkaninfo
de: kscreen-console,kscreen-doctor gpu: corectrl wl: wayland-info
x11: xdpyinfo, xprop, xrandr
Audio:
Device-1: Intel Lunar Lake-M HD Audio vendor: Lenovo
driver: sof-audio-pci-intel-lnl bus-ID: 00:1f.3 chip-ID: 8086:a828
class-ID: 0401
API: ALSA v: k7.0.0-rc7-1-cachyos-rc status: kernel-api
Server-1: sndiod v: N/A status: off
Server-2: JACK v: 0.126.0 status: off
Server-3: PipeWire v: 1.6.2 status: active with: 1: pipewire-pulse
status: active 2: wireplumber status: active 3: pipewire-alsa type: plugin
Network:
Device-1: Intel BE201 320MHz driver: iwlwifi v: kernel port: N/A
bus-ID: 00:14.3 chip-ID: 8086:a840 class-ID: 0280
IF: wlan0 state: up mac:
IF-ID-1: tun0 state: unknown speed: 10000 Mbps duplex: full mac: N/A
Bluetooth:
Device-1: Intel driver: btintel_pcie v: 0.1 bus-ID: 00:14.7
chip-ID: 8086:a876 class-ID: 0d11
Report: btmgmt ID: hci0 rfk-id: 2 state: up address: bt-v: 5.4
lmp-v: 13 class-ID: 7c0000
Drives:
Local Storage: total: 953.87 GiB used: 218.35 GiB (22.9%)
ID-1: /dev/nvme0n1 vendor: Western Digital model: WD PC SN7100S
SDFPMSL-1T00-1101 size: 953.87 GiB speed: 63.2 Gb/s lanes: 4 tech: SSD
serial: fw-rev: 7611M001 temp: 27.9 C scheme: GPT
Partition:
ID-1: / size: 951.87 GiB used: 218.1 GiB (22.9%) fs: btrfs
dev: /dev/nvme0n1p2
ID-2: /boot size: 2 GiB used: 248.4 MiB (12.2%) fs: vfat
dev: /dev/nvme0n1p1
ID-3: /home size: 951.87 GiB used: 218.1 GiB (22.9%) fs: btrfs
dev: /dev/nvme0n1p2
ID-4: /var/log size: 951.87 GiB used: 218.1 GiB (22.9%) fs: btrfs
dev: /dev/nvme0n1p2
ID-5: /var/tmp size: 951.87 GiB used: 218.1 GiB (22.9%) fs: btrfs
dev: /dev/nvme0n1p2
Swap:
ID-1: swap-1 type: zram size: 30.85 GiB used: 0 KiB (0.0%) priority: 100
dev: /dev/zram0
Sensors:
System Temperatures: cpu: N/A mobo: N/A
Fan Speeds (rpm): cpu: 0
Info:
Memory: total: 32 GiB note: est. available: 30.86 GiB used: 5.08 GiB (16.5%)
Processes: 433 Power: uptime: 1h 3m states: freeze,mem,disk
suspend: s2idle wakeups: 0 hibernate: platform Init: systemd v: 260
default: graphical
Packages: pm: pacman pkgs: 1402 Compilers: clang: 22.1.2 gcc: 15.2.1
Shell: fish v: 4.6.0 running-in: konsole inxi: 3.3.40