Backlight control was working with kernel 5.9.1 and driver 455.23.
I am now on kernel 5.9.9 and driver 455.45.01 and it stopped working.
Tried reverting back to kernel 5.9.1 and drivers 455.23… but no luck. I’m not sure how to proceed since I cannot replicate my old configuration, and it just stopped working.
The laptop is in Discrete mode, with only the NVIDIA graphics card enabled, the integrated AMD gpu is disabled. In Windows everything works fine.
Are the new drivers disabling / ignoring the “RegistryDwords” “EnableBrightnessControl=1;” Xorg option?
There are many threads online discussing this, but none of the solutions work. This appears to be a widespread problem and it occurs in both Discrete and Hybrid graphics mode selected on the BIOS. https://bbs.archlinux.org/viewtopic.php?id=253568
i have the intel variant of the legion 5 but 2 things were needed for backlight control, enabling brightness control in the xorg configuration as you mentioned above and making sure acpid.service is enabled/running
Loaded: loaded (/usr/lib/systemd/system/acpid.service; enabled; vendor preset: disabled)
Active: active (running) since Tue 2020-11-24 15:16:03 EST; 2min 33s ago
Docs: man:acpid(8)
Main PID: 464 (acpid)
Tasks: 1 (limit: 19051)
Memory: 476.0K
CGroup: /system.slice/acpid.service
└─464 /usr/bin/acpid --foreground --netlink
Nov 24 15:17:22 archlinux root[2399]: ACPI group/action undefined: video/brightnessup / BRTUP
Nov 24 15:17:22 archlinux root[2409]: ACPI group/action undefined: video/brightnessup / BRTUP
Nov 24 15:17:22 archlinux root[2414]: ACPI group/action undefined: video/brightnessup / BRTUP
Nov 24 15:17:22 archlinux root[2419]: ACPI group/action undefined: video/brightnessup / BRTUP
Nov 24 15:18:32 archlinux root[2627]: ACPI group/action undefined: video/brightnessup / BRTUP
Nov 24 15:18:33 archlinux root[2646]: ACPI group/action undefined: video/brightnessup / BRTUP
Nov 24 15:18:35 archlinux root[2740]: ACPI group/action undefined: video/brightnessup / BRTUP
Nov 24 15:18:35 archlinux root[2750]: ACPI group/action undefined: video/brightnessup / BRTUP
Nov 24 15:18:35 archlinux root[2755]: ACPI group/action undefined: video/brightnessup / BRTUP
Nov 24 15:18:35 archlinux root[2762]: ACPI group/action undefined: video/brightnessup / BRTUP
@dglt unfortunately that doesn’t work for me, I think the AMD and Intel version might be different in this regard.
acpid is enabled, but no brightness events are registered when I press the keys. Are you using the laptop in Discrete or Hybrid mode? I believe that also plays a major role. Did you also had to add any acpi_backlight= option to the command line?
This is really a bummer, it was working, and I have no idea why it stopped…
enabling brightness control (as an nvidia xorg option) only works on discrete mode which i spend 99% of my time on, im not currently using acpi_backlight parameters.
i’m not sure if it matters but why the " ; " after "EnableBrightnessControl=1"? unless you have other options on the same line you shouldnt need it.
edit: works for me on arch main kernel ‘linux’ and ‘linux-zen’
i was on the vulkan beta but im back on 455.45.01 now. i was wrong about acpid because i have it disabled now since it was causing the nvidia gpu to stay on its lowest clock which it wasnt before. even with acpid disabled i still have backlight on discrete mode as long as “EnableBrightnessControl=1” is used. this should show in
I purged all nvidia drivers, binaries, modules, all configuration files, etc. Rebooted fresh into an environment without any nvidia stuff. Then proceeded to reinstall everything with the 455.45.01 driver.
The backlight control is back and I’m none the wiser… except that from now on I will always make sure I purge all configuration and all drivers etc before I install new ones.