Quadro P5200 max birghtness problem on DELL Precision 7730

I use Manjaro Deepin, after some recent updates (couple of months actually) i have a problem where max brightness value is very low (on each boot, and when you try to change it with buttons / through Deepin settings).

I think it’s most likely nvidia driver (current version is 430.26 and previous also affected was 418.24), but can’t be too sure…

Was trying to figure out and isolate issue on Manjaro forums, here’s what we found out so far:

  1. Did clean installation (manjaro-deepin-18.0.2-stable-x86_64.iso):
  • At first i was on 4.19 LTS (which is default on this .iso and everything was fine)
  • Then i’ve updated system to current state - issue become apparent.
  • Then i’ve updated to 5.1.15-1 Kernel, which changed nothing in that sense

So i think that should mean it’s not Kernel itself.

  1. Found out that problem is here:
    cat /sys/class/backlight/nvidia_0/max_brightnes

cat /sys/class/backlight/nvidia_0/brightnes

  • If i manually change /sys/class/backlight/nvidia_0/brightnes value to 100 - it will work perfectly fine, like before update.
  • Also when changing by buttons / Deepin settings - it works prfectly fine, system now think that 100 is max brightness value and acts this way.
  • On next reboot cat /sys/class/backlight/nvidia_0/brightnes goes back to 42.
  1. We found probably related bug described in nouveau driver https://bugs.freedesktop.org/show_bug.cgi?id=110407

So…What could potentially reset /sys/class/backlight/nvidia_0/brightnes to 42 on every boot after some updates?

  • Nvidia driver
  • Kernel
  • Deepin (which known to be supper buggy, but that looks like some system level stuff, not de…)

Please help to solve this.
Hopefully it can be fixed, and soon :)

inxi -Fxxz

System:    Host: x133-pc Kernel: 5.1.15-1-MANJARO x86_64 bits: 64 compiler: gcc v: 9.1.0 Desktop: Deepin 15.10.1 tk: Qt 5.12.4 
           wm: DeepinWM dm: LightDM Distro: Manjaro Linux 
Machine:   Type: Laptop System: Dell product: Precision 7730 v: N/A serial: <filter> Chassis: type: 10 serial: <filter> 
           Mobo: Dell model: 0VC5H3 v: A00 serial: <filter> UEFI: Dell v: 1.6.0 date: 12/25/2018 
Battery:   ID-1: BAT0 charge: 93.5 Wh condition: 94.1/97.0 Wh (97%) volts: 12.0/11.4 model: BYD DELL GW0K986 serial: <filter> 
           status: Discharging 
CPU:       Topology: 6-Core model: Intel Core i9-8950HK bits: 64 type: MT MCP arch: Kaby Lake rev: A L2 cache: 12.0 MiB 
           flags: avx avx2 lm nx pae sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx bogomips: 69720 
           Speed: 800 MHz min/max: 800/4800 MHz Core speeds (MHz): 1: 800 2: 800 3: 800 4: 800 5: 800 6: 800 7: 801 8: 801 
           9: 800 10: 800 11: 799 12: 800 
Graphics:  Device-1: NVIDIA GP104GLM [Quadro P5200 Mobile] vendor: Dell driver: nvidia v: 430.26 bus ID: 01:00.0 
           chip ID: 10de:1bb5 
           Display: x11 server: X.Org 1.20.5 driver: nvidia resolution: 3840x2160~60Hz 
           OpenGL: renderer: Quadro P5200/PCIe/SSE2 v: 4.6.0 NVIDIA 430.26 direct render: Yes 
Audio:     Device-1: Intel Cannon Lake PCH cAVS vendor: Dell driver: snd_hda_intel v: kernel bus ID: 00:1f.3 
           chip ID: 8086:a348 
           Device-2: NVIDIA GP104 High Definition Audio vendor: Dell driver: snd_hda_intel v: kernel bus ID: 01:00.1 
           chip ID: 10de:10f0 
           Sound Server: ALSA v: k5.1.15-1-MANJARO 
Network:   Device-1: Intel Ethernet I219-LM vendor: Dell driver: e1000e v: 3.2.6-k port: efa0 bus ID: 00:1f.6 
           chip ID: 8086:15bb 
           IF: eno1 state: down mac: <filter> 
           Device-2: Intel Wireless-AC 9260 driver: iwlwifi v: kernel port: 3000 bus ID: 6f:00.0 chip ID: 8086:2526 
           IF: wlp111s0 state: up mac: <filter> 
Drives:    Local Storage: total: 267.35 GiB used: 11.59 GiB (4.3%) 
           ID-1: /dev/nvme0n1 vendor: Samsung model: PM981 NVMe 256GB size: 238.47 GiB speed: 31.6 Gb/s lanes: 4 
           serial: <filter> 
           ID-2: /dev/sda type: USB vendor: Kingston model: DataTraveler 3.0 size: 28.88 GiB serial: <filter> 
Partition: ID-1: / size: 109.49 GiB used: 11.48 GiB (10.5%) fs: ext4 dev: /dev/nvme0n1p2 
Sensors:   System Temperatures: cpu: 39.0 C mobo: N/A gpu: nvidia temp: 34 C 
           Fan Speeds (RPM): cpu: 0 fan-2: 0 
Info:      Processes: 265 Uptime: N/A Memory: 62.75 GiB used: 782.4 MiB (1.2%) Init: systemd v: 242 Compilers: gcc: 9.1.0 
           Shell: bash v: 5.0.7 running in: deepin-terminal inxi: 3.0.34

Brightness values like audio volume values have to be saved/restored by the distro system, e.g. by the DE or a systemd unit. The driver doesn’t touch it.

Oh well…Ok, thanks for the heads up, i’ll try to contact Deepin then, since Manjaro doesn’t have a clue what could cause it.