Cannot adjust brightness on Legion 5 15ACH6

I'm loving this distro so far, I've previously ran Arch on my desktop, but it was to much of a pain to set up with all of the driver stuff I would have to have dealt with on this laptop. All of my other issues have been fixed without me having to do anything just by installing this (Wifi, optimus, etc.) However it seems I cannot control the display brightness within KDE, the brightness slider changes, but the brightness does not. it seems like it is modifying the file to control the backlight, /sys/class/backlight/amdgpu-bl0/brightness, and /sys/class/backlight/amdgpu-bl0/actual-brightness give the same number as /sys/class/backlight/amdgpu-bl0/brightness, but the brightness doesn't change. Idk if this is something you can troubleshoot or if this is a driver/kernel issue, but I don't really know where the correct place for an issue would be.

parameters: BOOT_IMAGE=/@/boot/vmlinuz-linux-zen root=UUID=e481bbf4-a9d2-4d02-9013-2a23282cb1a3  
rw [email protected] quiet
cryptdevice=UUID=41b29b37-3f81-495c-a303-09155fd103f9:luks-41b29b37-3f81-495c-a303-09155fd103f9
root=/dev/mapper/luks-41b29b37-3f81-495c-a303-09155fd103f9 splash rd.udev.log_priority=3
vt.global_cursor_default=0 systemd.unified_cgroup_hierarchy=1
resume=/dev/mapper/luks-8b916ad5-70ec-4bf8-87b2-8c8d70a85e77 loglevel=3 amdgpu.backlight=0
acpi_backlight=video
Desktop: KDE Plasma 5.22.5 tk: Qt 5.15.2 info: latte-dock wm: kwin_x11 vt: 1 dm: SDDM  
Distro: Garuda Linux base: Arch Linux  
Machine:   Type: Laptop System: LENOVO product: 82JW v: Legion 5 15ACH6 serial: <filter> Chassis: type: 10  
v: Legion 5 15ACH6 serial: <filter>  
Mobo: LENOVO model: LNVNB161216 v: SDK0R32862 WIN serial: <filter> UEFI: LENOVO v: HHCN18WW  
date: 08/30/2021  
Battery:   ID-1: BAT0 charge: 50.5 Wh (84.0%) condition: 60.1/60.0 Wh (100.2%) volts: 17.4 min: 15.4  
model: Celxpert L20C4PC0 type: Li-poly serial: <filter> status: Charging cycles: 23  
CPU:       Info: 8-Core model: AMD Ryzen 7 5800H with Radeon Graphics bits: 64 type: MT MCP arch: Zen 3  
family: 19 (25) model-id: 50 (80) stepping: 0 microcode: A50000C cache: L2: 4 MiB  
flags: avx avx2 lm nx pae sse sse2 sse3 sse4_1 sse4_2 sse4a ssse3 svm bogomips: 102206  
Speed: 1482 MHz min/max: 1200/3200 MHz boost: enabled Core speeds (MHz): 1: 1482 2: 3113  
3: 1895 4: 1958 5: 2006 6: 1401 7: 1847 8: 3344 9: 3190 10: 2313 11: 1915 12: 1845 13: 1792  
14: 1570 15: 1696 16: 2392  
Vulnerabilities: Type: itlb_multihit status: Not affected  
Type: l1tf status: Not affected  
Type: mds status: Not affected  
Type: meltdown status: Not affected  
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: Full AMD retpoline, IBPB: conditional, IBRS_FW, STIBP: always-on, RSB filling  
Type: srbds status: Not affected  
Type: tsx_async_abort status: Not affected  
Graphics:  Device-1: NVIDIA GA107BM [GeForce RTX 3050 Ti Mobile] vendor: Lenovo driver: nvidia v: 470.74  
alternate: nouveau,nvidia_drm bus-ID: 01:00.0 chip-ID: 10de:25e0 class-ID: 0300  
Device-2: AMD Cezanne vendor: Lenovo driver: amdgpu v: kernel bus-ID: 06:00.0  
chip-ID: 1002:1638 class-ID: 0300  
Display: x11 server: X.Org 1.20.13 compositor: kwin_x11 driver: loaded: modesetting,nvidia  
display-ID: :0 screens: 1  
Screen-1: 0 s-res: 1920x1080 s-dpi: 96 s-size: 508x285mm (20.0x11.2") s-diag: 582mm (22.9")  
Monitor-1: eDP-1 res: 1920x1080 hz: 165 dpi: 142 size: 344x194mm (13.5x7.6")  
diag: 395mm (15.5")  
OpenGL: renderer: AMD RENOIR (DRM 3.42.0 5.14.11-zen1-1-zen LLVM 12.0.1) v: 4.6 Mesa 21.2.3  
direct render: Yes  
Audio:     Device-1: NVIDIA vendor: Lenovo driver: snd_hda_intel v: kernel bus-ID: 01:00.1  
chip-ID: 10de:2291 class-ID: 0403  
Device-2: AMD Raven/Raven2/FireFlight/Renoir Audio Processor vendor: Lenovo driver: N/A  
alternate: snd_pci_acp3x, snd_rn_pci_acp3x bus-ID: 06:00.5 chip-ID: 1022:15e2 class-ID: 0480  
Device-3: AMD Family 17h HD Audio vendor: Lenovo driver: snd_hda_intel v: kernel  
bus-ID: 06:00.6 chip-ID: 1022:15e3 class-ID: 0403  
Sound Server-1: ALSA v: k5.14.11-zen1-1-zen running: yes  
Sound Server-2: JACK v: 1.9.19 running: no  
Sound Server-3: PulseAudio v: 15.0 running: no  
Sound Server-4: PipeWire v: 0.3.38 running: yes  
Network:   Device-1: Realtek RTL8111/8168/8411 PCI Express Gigabit Ethernet vendor: Lenovo driver: r8169  
v: kernel port: 3000 bus-ID: 03:00.0 chip-ID: 10ec:8168 class-ID: 0200  
IF: eno1 state: down mac: <filter>  
Device-2: Realtek vendor: Lenovo driver: rtw89_pci v: N/A modules: rtw89pci port: 2000  
bus-ID: 04:00.0 chip-ID: 10ec:8852 class-ID: 0280  
IF: wlp4s0 state: up mac: <filter>  
Bluetooth: Device-1: Realtek Bluetooth Radio type: USB driver: btusb v: 0.8 bus-ID: 3-4:3  
chip-ID: 0bda:4852 class-ID: e001 serial: <filter>  
Report: bt-adapter ID: hci0 rfk-id: 3 state: down bt-service: enabled,running rfk-block:  
hardware: no software: yes address: <filter>  
Drives:    Local Storage: total: 1.38 TiB used: 18.49 GiB (1.3%)  
SMART Message: Unable to run smartctl. Root privileges required.
ID-1: /dev/nvme0n1 maj-min: 259:1 vendor: SK Hynix model: HFS512GDE9X084N size: 476.94 GiB
block-size: physical: 512 B logical: 512 B speed: 31.6 Gb/s lanes: 4 type: SSD serial: <filter>
rev: 41010C22 temp: 38.9 C scheme: GPT
ID-2: /dev/nvme1n1 maj-min: 259:0 vendor: Western Digital model: WDS100T2B0C-00PXH0
size: 931.51 GiB block-size: physical: 512 B logical: 512 B speed: 31.6 Gb/s lanes: 4 type: SSD
serial: <filter> rev: 211070WD temp: 25.9 C scheme: GPT
Partition: ID-1: / raw-size: 460.73 GiB size: 460.73 GiB (100.00%) used: 18.49 GiB (4.0%) fs: btrfs
dev: /dev/dm-0 maj-min: 254:0 mapped: luks-41b29b37-3f81-495c-a303-09155fd103f9
ID-2: /boot/efi raw-size: 260 MiB size: 256 MiB (98.46%) used: 706 KiB (0.3%) fs: vfat
dev: /dev/nvme0n1p1 maj-min: 259:2
ID-3: /home raw-size: 460.73 GiB size: 460.73 GiB (100.00%) used: 18.49 GiB (4.0%) fs: btrfs
dev: /dev/dm-0 maj-min: 254:0 mapped: luks-41b29b37-3f81-495c-a303-09155fd103f9
ID-4: /var/log raw-size: 460.73 GiB size: 460.73 GiB (100.00%) used: 18.49 GiB (4.0%) fs: btrfs
dev: /dev/dm-0 maj-min: 254:0 mapped: luks-41b29b37-3f81-495c-a303-09155fd103f9
ID-5: /var/tmp raw-size: 460.73 GiB size: 460.73 GiB (100.00%) used: 18.49 GiB (4.0%) fs: btrfs
dev: /dev/dm-0 maj-min: 254:0 mapped: luks-41b29b37-3f81-495c-a303-09155fd103f9
Swap:      Kernel: swappiness: 133 (default 60) cache-pressure: 100 (default)
ID-1: swap-1 type: zram size: 14.5 GiB used: 2.5 MiB (0.0%) priority: 100 dev: /dev/zram0
ID-2: swap-2 type: partition size: 15.94 GiB used: 0 KiB (0.0%) priority: -2 dev: /dev/dm-1
maj-min: 254:1 mapped: luks-8b916ad5-70ec-4bf8-87b2-8c8d70a85e77
Sensors:   Message: No sensor data found. Is lm-sensors configured?
Info:      Processes: 355 Uptime: 14m wakeups: 1 Memory: 14.5 GiB used: 2.84 GiB (19.6%) Init: systemd
v: 249 tool: systemctl Compilers: gcc: 11.1.0 clang: 12.0.1 Packages: pacman: 1547 lib: 440
Shell: fish v: 3.3.1 running-in: konsole inxi: 3.3.06```

Hi there, welcome!
I think it could be a known problem.
The Arch wiki says for legion 5i "Cannot change brightness in dynamic graphics mode as of Linux 5.12.13 (26 June 2021).".
Your model is slightly different but I think it could have the same issue.
https://wiki.archlinux.org/title/Laptop/Lenovo#Legion_series

2 Likes