Nvidia Optimus laptop with bbswitch: backlight issues

Asus GL552VW, Intel+Nvidia GTX 960m, KDE.
After installing bbswitch-dkms to switch the GPUs with optimus-manager, brightness keys no longer work as intended.
Before bbswitch, doing an ls on /sys/class/backlight/ showed intel_backlight, and the KDE OSD showed said backlight brightness changes in increments/decrements of 5%.

After installing bbswitch, configuring optimus-manager and booting with the iGPU, backlight controls wont work as before, doing again an ls over /sys/class/backlight shows acpi_video0 and intel_backlight.
Keys work, but the KDE OSD for backlight no longer report changes.
Brightness still changes (in increments/decrements of 10%).

What i tried:
GRUB paramaters: acpi_backlight=native makes the brightness key stop working, and acpi_backlight=vendor, makes the keys work, but still 10% steps and still no brightness OSD.

inxi -Fxxxza output: 
System:    Kernel: 5.11.15-148-tkg-bmq x86_64 bits: 64 compiler: gcc v: 10.2.0  
parameters: intel_pstate=passive BOOT_IMAGE=/@/boot/vmlinuz-linux-tkg-bmq  
root=UUID=ffcf29e9-7b57-47e6-b66c-a92051aac4e6 rw [email protected] quiet acpi_osi=!
"acpi_osi=Windows 2009" acpi_backlight=vendor nouveau_modeset=0
cryptdevice=UUID=02567c77-047e-4b3d-a5fb-a14df7878685:luks-02567c77-047e-4b3d-a5fb-a14df7878685
root=/dev/mapper/luks-02567c77-047e-4b3d-a5fb-a14df7878685 splash rd.udev.log_priority=3
vt.global_cursor_default=0 systemd.unified_cgroup_hierarchy=1
resume=/dev/mapper/luks-2a2ec776-7b59-43b5-8e90-48239c67efe5 loglevel=3
Desktop: KDE Plasma 5.21.4 tk: Qt 5.15.2 info: latte-dock wm: kwin_x11 vt: 2 dm: SDDM  
Distro: Garuda Linux base: Arch Linux  
Machine:   Type: Laptop System: ASUSTeK product: GL552VW v: 1.0 serial: <filter>  
Mobo: ASUSTeK model: GL552VW v: 1.0 serial: <filter> UEFI: American Megatrends v: GL552VW.304  
date: 04/25/2019  
Battery:   ID-1: BAT0 charge: 32.8 Wh (100.0%) condition: 32.8/48.0 Wh (68.4%) volts: 15.0 min: 15.0  
model: ASUSTeK ASUS Battery type: Li-ion serial: N/A status: Not charging cycles: 219  
CPU:       Info: Quad Core model: Intel Core i5-6300HQ bits: 64 type: MCP arch: Skylake-S family: 6  
model-id: 5E (94) stepping: 3 microcode: E2 cache: L2: 6 MiB  
flags: avx avx2 lm nx pae sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx bogomips: 18416  
Speed: 1958 MHz min/max: 800/3200 MHz Core speeds (MHz): 1: 1958 2: 1929 3: 2985 4: 3001  
Vulnerabilities: Type: itlb_multihit status: KVM: VMX disabled  
Type: l1tf mitigation: PTE Inversion; VMX: conditional cache flushes, SMT disabled  
Type: mds mitigation: Clear CPU buffers; SMT disabled  
Type: meltdown mitigation: PTI  
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 generic retpoline, IBPB: conditional, IBRS_FW, STIBP: disabled, RSB filling  
Type: srbds mitigation: Microcode  
Type: tsx_async_abort mitigation: Clear CPU buffers; SMT disabled  
Graphics:  Device-1: Intel HD Graphics 530 vendor: ASUSTeK driver: i915 v: kernel bus-ID: 00:02.0  
chip-ID: 8086:191b class-ID: 0300  
Device-2: NVIDIA GM107M [GeForce GTX 960M] driver: N/A alternate: nouveau, nvidia_drm, nvidia  
bus-ID: 01:00.0 chip-ID: 10de:139b class-ID: 0302  
Display: x11 server: X.Org 1.20.11 compositor: kwin_x11 driver: loaded: modesetting  
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: 60 dpi: 142 size: 344x193mm (13.5x7.6") diag: 394mm (15.5")  
OpenGL: renderer: Mesa Intel HD Graphics 530 (SKL GT2) v: 4.6 Mesa 21.0.3 direct render: Yes  
Audio:     Device-1: Intel 100 Series/C230 Series Family HD Audio vendor: ASUSTeK driver: snd_hda_intel  
v: kernel bus-ID: 00:1f.3 chip-ID: 8086:a170 class-ID: 0403  
Sound Server-1: ALSA v: k5.11.15-148-tkg-bmq running: yes  
Sound Server-2: JACK v: 1.9.18 running: no  
Sound Server-3: PulseAudio v: 14.2 running: no  
Sound Server-4: PipeWire v: 0.3.26 running: yes  
Network:   Device-1: Intel Wireless 3160 driver: iwlwifi v: kernel port: f040 bus-ID: 02:00.0  
chip-ID: 8086:08b3 class-ID: 0280  
IF: wlp2s0 state: up mac: <filter>  
Device-2: Realtek RTL8111/8168/8411 PCI Express Gigabit Ethernet vendor: ASUSTeK driver: r8169  
v: kernel port: d000 bus-ID: 03:00.1 chip-ID: 10ec:8168 class-ID: 0200  
IF: enp3s0f1 state: down mac: <filter>  
Bluetooth: Device-1: Intel Bluetooth wireless interface type: USB driver: btusb v: 0.8 bus-ID: 1-9:3  
chip-ID: 8087:07dc class-ID: e001  
Report: bt-adapter ID: hci0 rfk-id: 0 state: up address: <filter>  
Drives:    Local Storage: total: 1.13 TiB used: 289.82 GiB (25.1%)  
SMART Message: Unable to run smartctl. Root privileges required.  
ID-1: /dev/sda maj-min: 8:0 vendor: Seagate model: ST1000LM035-1RK172 size: 931.51 GiB  
block-size: physical: 4096 B logical: 512 B speed: 6.0 Gb/s rotation: 5400 rpm serial: <filter>  
rev: LCM2 scheme: GPT  
ID-2: /dev/sdb maj-min: 8:16 vendor: Western Digital model: WDS240G2G0B-00EPW0 size: 223.57 GiB
block-size: physical: 512 B logical: 512 B speed: 6.0 Gb/s rotation: SSD serial: <filter>
rev: 0400 scheme: GPT
Partition: ID-1: / raw-size: 210.66 GiB size: 210.66 GiB (100.00%) used: 31.19 GiB (14.8%) fs: btrfs
dev: /dev/dm-0 maj-min: 254:0 mapped: luks-02567c77-047e-4b3d-a5fb-a14df7878685
ID-2: /boot/efi raw-size: 256 MiB size: 252 MiB (98.46%) used: 682 KiB (0.3%) fs: vfat
dev: /dev/sdb1 maj-min: 8:17
ID-3: /home raw-size: 210.66 GiB size: 210.66 GiB (100.00%) used: 31.19 GiB (14.8%) fs: btrfs
dev: /dev/dm-0 maj-min: 254:0 mapped: luks-02567c77-047e-4b3d-a5fb-a14df7878685
ID-4: /var/log raw-size: 210.66 GiB size: 210.66 GiB (100.00%) used: 31.19 GiB (14.8%)
fs: btrfs dev: /dev/dm-0 maj-min: 254:0 mapped: luks-02567c77-047e-4b3d-a5fb-a14df7878685
ID-5: /var/tmp raw-size: 210.66 GiB size: 210.66 GiB (100.00%) used: 31.19 GiB (14.8%)
fs: btrfs dev: /dev/dm-0 maj-min: 254:0 mapped: luks-02567c77-047e-4b3d-a5fb-a14df7878685
Swap:      Kernel: swappiness: 10 (default 60) cache-pressure: 75 (default 100)
ID-1: swap-1 type: partition size: 12.65 GiB used: 0 KiB (0.0%) priority: -2 dev: /dev/dm-1
maj-min: 254:1 mapped: luks-2a2ec776-7b59-43b5-8e90-48239c67efe5
ID-2: swap-2 type: zram size: 2.88 GiB used: 0 KiB (0.0%) priority: 32767 dev: /dev/zram0
ID-3: swap-3 type: zram size: 2.88 GiB used: 0 KiB (0.0%) priority: 32767 dev: /dev/zram1
ID-4: swap-4 type: zram size: 2.88 GiB used: 0 KiB (0.0%) priority: 32767 dev: /dev/zram2
ID-5: swap-5 type: zram size: 2.88 GiB used: 0 KiB (0.0%) priority: 32767 dev: /dev/zram3
Sensors:   System Temperatures: cpu: 56.0 C mobo: N/A
Fan Speeds (RPM): cpu: 1300
Info:      Processes: 226 Uptime: 14m wakeups: 1 Memory: 11.5 GiB used: 3.7 GiB (32.1%) Init: systemd
v: 248 tool: systemctl Compilers: gcc: 10.2.0 clang: 11.1.0 Packages: pacman: 1549 lib: 514
Shell: fish v: 3.2.1 running-in: konsole inxi: 3.3.04

Read

please
and post

inxi -Fxxxza

as text! Even if you personally think it is unnecessary.

Edited, sorry for the very bad post, i was in a hurry and i did my poorest. Hopefully the edits help better understanding the issue.

I have "equalized" your text a few paragraphs make reading immensely easier and formatted the terminal output.
Please read what I posted above as links.

2 Likes

Since brightness is controllable with keys (and KDE Power settings?), this missing feedback seems to be a KDE bug.
I suggest you check for similar open bugs at KDE Bugs and contribute upstream.

1 Like

Yes, you may be right, i can reproduce the bug on pure Arch with KDE, so it's either a bug, or an unimplemented feature.

It happens when there are more than one backlight produced.
If you know which one is the one you need, mask the rest of them. (I did so, for mine :wink: ).