FS#58296 - [linux] Can't adjust backlight brightness anymore since kernel 4.16
Attached to Project:
Arch Linux
Opened by Jürgen Feste (jf25) - Saturday, 21 April 2018, 09:11 GMT
Last edited by Jan Alexander Steffens (heftig) - Thursday, 03 May 2018, 08:07 GMT
Opened by Jürgen Feste (jf25) - Saturday, 21 April 2018, 09:11 GMT
Last edited by Jan Alexander Steffens (heftig) - Thursday, 03 May 2018, 08:07 GMT
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Details
Description:
The update of the linux kernel from 4.15.15-1 to 4.16.3-1 broke my backlight control. I can no longer adjust its brightness by either the Fn keys nor by software. The directory /sys/class/backlight/ is just empty. It used to contain acpi_video0 and acpi_video1 (I don't know why there where two subdirectories for 1 screen). My laptop is a MSI CX70 from 2012. I have two GPUs which I both run with open drivers (intel and nouveau): [code]% lspci | grep VGA 00:02.0 VGA compatible controller: Intel Corporation 3rd Gen Core processor Graphics Controller (rev 09) 01:00.0 VGA compatible controller: NVIDIA Corporation GK107M [GeForce GT 640M] (rev a1)[/code] Switching the whole screen off via [code]xset dpms force off[/code] still works. Additional info: * package version(s) linux 4.16.3-1 * config and/or log files etc. Steps to reproduce: - boot the system - ls /sys/class/backlight/ shows empty directory |
This task depends upon
Closed by Jan Alexander Steffens (heftig)
Thursday, 03 May 2018, 08:07 GMT
Reason for closing: Fixed
Additional comments about closing: 4.16.6
Thursday, 03 May 2018, 08:07 GMT
Reason for closing: Fixed
Additional comments about closing: 4.16.6
dmesg-4.15.15-1.log (55.8 KiB)
I'm using nvidia driver. Problem is present on both linux and linux-lts packages.
I tried acpi_backlight values (with linux/nvidia, non-lts): none, vendor, video, native - without success.
linux-zen-4.16.3-1 - Backlight quit working
Downgrade to
linux-zen-4.15.15-1 - Backlight works fine
However...
linux-zen-4.16.3-1 & xf86-video-nouveau works fine as well.
Willing to troubleshoot, but I do need some guidance on where to start.
Can you try the boot option video.only_lcd=0
nvidia-340xx-dkms 340.106-30
Adding video.only_lcd=0 puts that back light to it's normal functioning.