Nvidia Optimus laptop with bbswitch: backlight issues

Issues & Assistance
#1

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
#2

Read

please
and post

inxi -Fxxxza

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

#3

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.

#4

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
#5

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
#6

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.

#7

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: ).