Screen brightness NOT adjustable using kernels 6.x

Support Graphics & Display
1

My LENOVO T14s is running MANJARO with kernel 5,15 and allows to set screen brightness using F5 / F6 keys.
I found this and switched to kernel 6.1 or 6.6 where these keys do not change anything.
Any proposal, how to solve this?

inxi --admin --verbosity=7 --filter --no-host --width
System:
  Kernel: 5.15.160-1-MANJARO arch: x86_64 bits: 64 compiler: gcc v: 14.1.1
    clocksource: hpet avail: acpi_pm
    parameters: BOOT_IMAGE=/boot/vmlinuz-5.15-x86_64
    root=UUID=3fb81935-3c2a-4b83-ae67-7b8f75e23839 rw apparmor=1
    security=apparmor resume=UUID=338139c5-0361-42c0-9573-dbd00f711a01
    udev.log_priority=3 acpi_backlight=none
  Desktop: KDE Plasma v: 6.0.5 tk: Qt v: N/A info: frameworks v: 6.2.0
    wm: kwin_x11 vt: 2 dm: SDDM Distro: Manjaro base: Arch Linux
Machine:
  Type: Laptop System: LENOVO product: 20UH001QGE v: ThinkPad T14s Gen 1
    serial: <superuser required> Chassis: type: 10 serial: <superuser required>
  Mobo: LENOVO model: 20UH001QGE v: SDK0J40697 WIN
    serial: <superuser required> part-nu: LENOVO_MT_20UH_BU_Think_FM_ThinkPad
    T14s Gen 1 uuid: <superuser required> UEFI: LENOVO v: R1CET65W(1.34 )
    date: 06/17/2021
Battery:
  ID-1: BAT0 charge: 19.3 Wh (42.7%) condition: 45.2/57.0 Wh (79.3%)
    power: 6.8 W volts: 11.3 min: 11.5 model: SMP 5B10W139 type: Li-poly
    serial: <filter> status: discharging cycles: 1775
Memory:
  System RAM: total: 32 GiB available: 30.58 GiB used: 3.01 GiB (9.8%)
  Message: For most reliable report, use superuser + dmidecode.
  Array-1: capacity: 64 GiB slots: 2 modules: 2 EC: None
    max-module-size: 32 GiB note: est.
  Device-1: Channel-A DIMM 0 type: DDR4 detail: synchronous unbuffered
    (unregistered) size: 16 GiB speed: 3200 MT/s volts: note: check curr: 1
    min: 1 max: 1 width (bits): data: 64 total: 64
    manufacturer: Micron Technology part-no: 4ATS2G64HZ-3G2B1 serial: N/A
  Device-2: Channel-B DIMM 0 type: DDR4 detail: synchronous unbuffered
    (unregistered) size: 16 GiB speed: 3200 MT/s volts: note: check curr: 1
    min: 1 max: 1 width (bits): data: 64 total: 64
    manufacturer: Micron Technology part-no: 4ATS2G64HZ-3G2B1 serial: N/A
CPU:
  Info: model: AMD Ryzen 7 PRO 4750U with Radeon Graphics bits: 64 type: MT MCP
    arch: Zen 2 gen: 3 level: v3 note: check built: 2020-22
    process: TSMC n7 (7nm) family: 0x17 (23) model-id: 0x60 (96) stepping: 1
    microcode: 0x8600106
  Topology: cpus: 1x cores: 8 tpc: 2 threads: 16 smt: enabled cache:
    L1: 512 KiB desc: d-8x32 KiB; i-8x32 KiB L2: 4 MiB desc: 8x512 KiB L3: 8 MiB
    desc: 2x4 MiB
  Speed (MHz): avg: 1423 high: 1813 min/max: 1400/1700 boost: enabled
    scaling: driver: acpi-cpufreq governor: schedutil cores: 1: 1433 2: 1813
    3: 1396 4: 1396 5: 1397 6: 1398 7: 1397 8: 1397 9: 1366 10: 1397 11: 1397
    12: 1397 13: 1397 14: 1397 15: 1397 16: 1395 bogomips: 54318
  Flags: 3dnowprefetch abm adx aes aperfmperf apic arat avic avx avx2 bmi1
    bmi2 bpext cat_l3 cdp_l3 clflush clflushopt clwb clzero cmov cmp_legacy
    constant_tsc cpb cpuid cqm cqm_llc cqm_mbm_local cqm_mbm_total
    cqm_occup_llc cr8_legacy cx16 cx8 de decodeassists extapic extd_apicid
    f16c flushbyasid fma fpu fsgsbase fxsr fxsr_opt ht hw_pstate ibpb ibrs ibs
    irperf lahf_lm lbrv lm mba mca mce misalignsse mmx mmxext monitor movbe
    msr mtrr mwaitx nonstop_tsc nopl npt nrip_save nx osvw overflow_recov pae
    pat pausefilter pclmulqdq pdpe1gb perfctr_core perfctr_llc perfctr_nb
    pfthreshold pge pni popcnt pse pse36 rapl rdpid rdpru rdrand rdseed rdt_a
    rdtscp rep_good sep sha_ni skinit smap smca smep ssbd sse sse2 sse4_1
    sse4_2 sse4a ssse3 stibp succor svm svm_lock syscall tce topoext tsc
    tsc_scale umip v_spec_ctrl v_vmsave_vmload vgif vmcb_clean vme vmmcall
    wbnoinvd wdt xgetbv1 xsave xsavec xsaveerptr xsaveopt
  Vulnerabilities:
  Type: gather_data_sampling 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: reg_file_data_sampling status: Not affected
  Type: retbleed mitigation: untrained return thunk; SMT enabled with STIBP
    protection
  Type: spec_rstack_overflow mitigation: safe RET
  Type: spec_store_bypass mitigation: Speculative Store Bypass disabled via
    prctl and seccomp
  Type: spectre_v1 mitigation: usercopy/swapgs barriers and __user pointer
    sanitization
  Type: spectre_v2 mitigation: Retpolines; IBPB: conditional; STIBP:
    always-on; RSB filling; PBRSB-eIBRS: Not affected; BHI: Not affected
  Type: srbds status: Not affected
  Type: tsx_async_abort status: Not affected
Graphics:
  Device-1: AMD Renoir [Radeon RX Vega 6 ] vendor: Lenovo driver: amdgpu
    v: kernel arch: GCN-5 code: Vega process: GF 14nm built: 2017-20 pcie: gen: 4
    speed: 16 GT/s lanes: 16 ports: active: eDP-1 empty: DP-1,DP-2,HDMI-A-1
    bus-ID: 06:00.0 chip-ID: 1002:1636 class-ID: 0300 temp: 46.0 C
  Device-2: IMC Networks Integrated Camera driver: uvcvideo type: USB
    rev: 2.0 speed: 480 Mb/s lanes: 1 mode: 2.0 bus-ID: 2-2:2 chip-ID: 13d3:5405
    class-ID: fe01 serial: <filter>
  Display: x11 server: X.Org v: 21.1.13 with: Xwayland v: 24.1.0
    compositor: kwin_x11 driver: X: loaded: amdgpu unloaded: modesetting
    alternate: fbdev,vesa dri: radeonsi gpu: amdgpu display-ID: :0 screens: 1
  Screen-1: 0 s-res: 1920x1080 s-dpi: 96 s-size: 508x285mm (20.00x11.22")
    s-diag: 582mm (22.93")
  Monitor-1: eDP-1 mapped: eDP model: ChiMei InnoLux 0x14f2 built: 2018
    res: 1920x1080 hz: 60 dpi: 158 gamma: 1.2 size: 309x173mm (12.17x6.81")
    diag: 354mm (13.9") ratio: 16:9 modes: max: 1920x1080 min: 640x480
  API: EGL v: 1.5 hw: drv: amd radeonsi platforms: device: 0 drv: radeonsi
    device: 1 drv: swrast gbm: drv: kms_swrast surfaceless: drv: radeonsi x11:
    drv: radeonsi inactive: wayland
  API: OpenGL v: 4.6 compat-v: 4.5 vendor: amd mesa v: 24.0.9-manjaro1.1
    glx-v: 1.4 direct-render: yes renderer: AMD Radeon Graphics (radeonsi renoir
    LLVM 17.0.6 DRM 3.42 5.15.160-1-MANJARO) device-ID: 1002:1636
    memory: 500 MiB unified: no
  API: Vulkan v: 1.3.279 layers: N/A device: 0 type: integrated-gpu name: AMD
    Radeon Graphics (RADV RENOIR) driver: mesa radv v: 24.0.9-manjaro1.1
    device-ID: 1002:1636 surfaces: xcb,xlib
2

You first have to check is it the video or is it the keys. Click on the battery icon and try from there, if it works then the problem is with the function keys.

3

Try removing this from your parameters as a test?

I don’t have this in my parameters and the Fn + F5 or F6 keys (in my case) do work with 6.1x and 6.6x LTS kernels.

1 Like
4

Thanks,

How / where to do this?

5

It should be in /etc/default/grub but I’m not 100% sure as I don’t know where the inxi program gets all its parameters from. Try cat /etc/default/grub to see if it shows there. If so you can use e.g. nano (with sudo) to remove it, then update-grub.

In this case you can do it temporarily using the “e” option in the GRUB boot menu.

I’ll be back when I can find other relevant config. files.

1 Like
6

Thank you, works! I had added the line earlier as F5 / F6-keys have not been working without that, ref. here:

  • acpi_backlight definition, to solve error systemctl --failed: systemd-backlight@backlight:acpi_video0.service. Options: vendor, native, none, video;
    source: Laptop/Lenovo - ArchWiki
  • acpi_backlight=vendor wrong: no reaction for F5/F6 and in systemsettings, brightness always low
  • acpi_backlight=video wrong: no reaction for F5/F6 and in systemsettings, brightness always max
  • acpi_backlight=none OK, : brightness can be changed with F5/F6 and in systemsettings.
    Source: Systemctl-failed: systemd-backlight
1 Like
7

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