Screen brightness cannot be changed after an OS upgrade

kottakoa · 08-23-2020, 07:10 AM

I recently did an upgrade from ubuntu 16.04 to 20.04. Before the upgrade I could adjust the screen brightness only with a 3rd party program (screen-brightness), but now that doesn't work either. I have/had both with X11.

lspci:

Code:

00:00.0 Host bridge: Intel Corporation Xeon E3-1200 v5/E3-1500 v5/6th Gen Core Processor Host Bridge/DRAM Registers (rev 07)
00:01.0 PCI bridge: Intel Corporation Xeon E3-1200 v5/E3-1500 v5/6th Gen Core Processor PCIe Controller (x16) (rev 07)
00:04.0 Signal processing controller: Intel Corporation Xeon E3-1200 v5/E3-1500 v5/6th Gen Core Processor Thermal Subsystem (rev 07)
00:14.0 USB controller: Intel Corporation 100 Series/C230 Series Chipset Family USB 3.0 xHCI Controller (rev 31)
00:14.2 Signal processing controller: Intel Corporation 100 Series/C230 Series Chipset Family Thermal Subsystem (rev 31)
00:15.0 Signal processing controller: Intel Corporation 100 Series/C230 Series Chipset Family Serial IO I2C Controller #0 (rev 31)
00:15.1 Signal processing controller: Intel Corporation 100 Series/C230 Series Chipset Family Serial IO I2C Controller #1 (rev 31)
00:16.0 Communication controller: Intel Corporation 100 Series/C230 Series Chipset Family MEI Controller #1 (rev 31)
00:17.0 SATA controller: Intel Corporation HM170/QM170 Chipset SATA Controller [AHCI Mode] (rev 31)
00:1c.0 PCI bridge: Intel Corporation 100 Series/C230 Series Chipset Family PCI Express Root Port #3 (rev f1)
00:1c.3 PCI bridge: Intel Corporation 100 Series/C230 Series Chipset Family PCI Express Root Port #4 (rev f1)
00:1f.0 ISA bridge: Intel Corporation HM170 Chipset LPC/eSPI Controller (rev 31)
00:1f.2 Memory controller: Intel Corporation 100 Series/C230 Series Chipset Family Power Management Controller (rev 31)
00:1f.3 Audio device: Intel Corporation 100 Series/C230 Series Chipset Family HD Audio Controller (rev 31)
00:1f.4 SMBus: Intel Corporation 100 Series/C230 Series Chipset Family SMBus (rev 31)
01:00.0 VGA compatible controller: NVIDIA Corporation GP106M [GeForce GTX 1060 Mobile] (rev a1)
01:00.1 Audio device: NVIDIA Corporation GP106 High Definition Audio Controller (rev a1)
02:00.0 Network controller: Intel Corporation Wireless 8260 (rev 3a)
03:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 10)

uname -r: 5.4.0-42-generic

I've tried, to no avail, the following ways to adjust the screen brightness:

function keys - a GUI indicator popups with an allegedly changed brightness value, not no effect
changing the brightness from the settings
f.lux
redshift
Editing /etc/default/grub with multiple suggested configurations (with sudo update-grub and reboot after each modification).
Editing /usr/share/X11/xorg.conf.d/80-backlight.conf and /usr/share/X11/xorg.conf.d/20-intel.conf (with reboots afterwards)
Editing directly /sys/class/backlight/acpi_video0/brightness and /sys/class/backlight/acpi_video1/brightness (they take values from 1 to 10) - values change, but with no apparent effect

xrandr doesn't work either:

Code:

$ xrandr
xrandr: Failed to get size of gamma for output default
Screen 0: minimum 1920 x 1080, current 1920 x 1080, maximum 1920 x 1080
default connected primary 1920x1080+0+0 0mm x 0mm
   1920x1080     77.00*

$ xrandr --output default --brightness 0.8
xrandr: Gamma size is 0.

$ xrandr --verbose |egrep '(Bright|Gamma)'
xrandr: Failed to get size of gamma for output default

Most of the solutions proposed online include adding acpi_backlight with some value to GRUB_CMDLINE_LINUX_DEFAULT in /etc/default/grub and then updating grub with sudo update-grub2 and finally rebooting. I've tried setting multiple values to it (video1, video, an empty string, nvidia, nouveau, intel, vendor, native), again to no avail.

I've also got bumblebee and both nouveau and proprietary nvidia drivers. Tried changing which drivers load by default in /etc/bumblebee/bumblebee.conf, but that doesn't seem to have any effect.

Finally, I made a bootable USB stick with Xubuntu and tried running that. Out of the box I could adjust screen brightness. I copied over the settings, which I suspect are relevant (GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" in /etc/default/grub and no files for backlight in /usr/share/X11/xorg.conf.d/), but that didn't help either.

Any other ideas?

JeremyBoden · 08-23-2020, 04:36 PM

Did you upgrade from 16.04 -> 18.04 -> 20.04? or did you install 20.04 and restore your data?

Have you tried a Ubuntu 20.04 DVD/USB to check out whether a clean system would work?

This might be an ideal time to consider dropping Ubuntu in favour of a better Linux.

nsk7even · 08-23-2020, 05:04 PM

I am using the xrandr solution to adjust the brightness of all my three displays, to avoid adjusting each one of it manually:
https://github.com/nsk7even/linux-to...r/system-tools

So generally this should work. But the error you are getting, may be the reason why xrandr is unable to adjust the brightness.
Check out if this helps: https://stackoverflow.com/a/47444992/2477582

I don't think that this is distribution related. But it may either occur due to some hardware issues (like the one referenced above), or due some old config files from the previous systems that interfer.

kottakoa · 08-24-2020, 03:37 PM

Quote:

Originally Posted by JeremyBoden

Did you upgrade from 16.04 -> 18.04 -> 20.04? or did you install 20.04 and restore your data?

Have you tried a Ubuntu 20.04 DVD/USB to check out whether a clean system would work?

This might be an ideal time to consider dropping Ubuntu in favour of a better Linux.

I upgraded from 16.04 -> 18.04 -> 20.04.

Will check 20.04 itself in due time - if it works, is there a way to quickly compare changes to system settings against the default configuration?

What are some better Linux distributions and why?

Quote:

Originally Posted by nsk7even

I am using the xrandr solution to adjust the brightness of all my three displays, to avoid adjusting each one of it manually:
https://github.com/nsk7even/linux-to...r/system-tools

So generally this should work. But the error you are getting, may be the reason why xrandr is unable to adjust the brightness.
Check out if this helps: https://stackoverflow.com/a/47444992/2477582

I don't think that this is distribution related. But it may either occur due to some hardware issues (like the one referenced above), or due some old config files from the previous systems that interfer.

Well, xrandr just returns the following with no effect to the brightness:

Code:

xrandr: Gamma size is 0.

I tried the SO suggestion; it didn't work either.

Quote:

But it may either occur ... due some old config files from the previous systems that interfer.

I think this is almost certainly the case - I kept a bunch of configs during the migration and most unwisely didn't keep the logs. It just didn't occur to me that something working in 16.04 wouldn't work in 20.04.

kottakoa · 08-26-2020, 04:27 PM

I tried an unmodified 20.04 from a live USB and the brightness can be controlled by the keyboard function keys. Is there some particular file or directory I need to check (other the ones mentioned)? What would be the next step?

nsk7even · 08-26-2020, 04:46 PM

This is difficult.

The easier option would be to make a fresh new install and migrate your applications and settings from the previous system. I know that this always is an obstacle ... but it isn't that hard than it looks like.

Additionally there are chances that other system parts or other applications are doing better then as well!
To make room for these chances, I always migrate as few config files as possible from a previous system.

kottakoa · 08-30-2020, 03:10 PM

Well, it finally boiled down to that. After some more futile messing with various suggestions, I installed a second ubuntu and the backlight works fine. The install menu didn't have an option to reinstall for some reason - will look to migrate data eventually. Thanks anyway.

nsk7even · 08-30-2020, 04:09 PM

Glad to hear that this was an acceptable option for you.

To be honest, I am not a friend of radical solutions and I always try to upgrade my systems as well, first.
But if a system's consistency degrades noticeable, it mostly makes no sense to try to fix this. I tried this in the past as well ... and it always was at least difficult and more time consuming than building a new system.

Nevertheless, I always try to upgrade the existing system first!
And I always have a 1:1 vital (=bootable) backup copy of the current system. This saves plenty of headaches ;-)

X00D45 · 09-04-2020, 09:01 AM

Hello Kottakoa....

I read you already solve this, but just for someone else how run with the same trouble...

I have the same problem with a some other distros ( Slackware ) , and also previous versions of Ubuntu .

I RE read your post , and I could see you tried setting the values in different files,but no this one

Quote:

/sys/class/backlight/intel_backlight/brightness

Just play with values in this file ==> /sys/class/backlight/intel_backlight/brightness .

With differents OS versions , the scale changes, but as long I tried , still working for me with different laptops and distributions.

NOTE : I have to run the command as ROOT ... eg.

Quote:

# echo 1600 > /sys/class/backlight/intel_backlight/brightness

Actually I'm using :

Quote:

> lsb_release -a

No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 19.10
Release: 19.10
Codename: eoan

Here the post where I got the answer...
https://askubuntu.com/questions/9674...n-ubuntu-17-10

But if still not working , may be you can try in https://askubuntu.com/

Please, let us know how it goes

All the best