I can't manage display brightness (XFCE)

insciwetrust · 2019-10-20 11:12:48

There is a bar that I can adjust, but it makes no difference, brightness stays the same. The option "Handle display brightness keys" is enabled.

Last edited by insciwetrust (2019-10-26 15:31:13)

seth · 2019-10-20 11:33:13

First figure whether and how you can manipulate the backlight the nerd way: https://wiki.archlinux.org/index.php/Backlight

insciwetrust · 2019-10-20 12:31:08

seth wrote:

First figure whether and how you can manipulate the backlight the nerd way: https://wiki.archlinux.org/index.php/Backlight

Nothing worked except installing clight from AUR and running it in the terminal. But now my brightness is 0 and I don't know how to adjust it.

Edit: Forgot to add, I am not able to launch the GUI of clight.

Edit 2: I realised that clight adjusts the brightness according to the ambient brightness. So when I took my laptop and put it next to a window, and then typed clight, the brightness increased. But still, I don't have control over it.

Last edited by insciwetrust (2019-10-20 13:18:38)

seth · 2019-10-20 13:33:49

What do you mean by "nothing worked"?

There's no /sys/class/backlight ?
How did you investigate on the setpci method? (Do NOT fire the example command blindly!!)
Did you read the notes on certain hardware? If so, you might have understood that the actual HW is actual pretty relevant to the matter. You might want to note it here…

The nerd way™ isn't to try some random frontend tools. clight might just operate the DPMS (ie. it turns your screen off but doesn't actually manipulate the backlight)

insciwetrust · 2019-10-20 13:50:34

seth wrote:

What do you mean by "nothing worked"?
There's no /sys/class/backlight ?
How did you investigate on the setpci method? (Do NOT fire the example command blindly!!)
Did you read the notes on certain hardware? If so, you might have understood that the actual HW is actual pretty relevant to the matter. You might want to note it here…
The nerd way™ isn't to try some random frontend tools. clight might just operate the DPMS (ie. it turns your screen off but doesn't actually manipulate the backlight)

There was intel_backlight, which had a max_brightness of 4648 and I wasn't able to manipulate the brightness of. I used the setpci command and nothing happened.

seth · 2019-10-20 14:01:47

I wasn't able to manipulate the brightness of

How in particular? Please read https://bbs.archlinux.org/viewtopic.php?id=57855
Did you see https://wiki.archlinux.org/index.php/Ba … ne_options ?
You've still not provided any details on the HW…

insciwetrust · 2019-10-20 14:41:28

seth wrote:

I wasn't able to manipulate the brightness of
How in particular? Please read https://bbs.archlinux.org/viewtopic.php?id=57855
Did you see https://wiki.archlinux.org/index.php/Ba … ne_options ?
You've still not provided any details on the HW…

I entered the code given with intel_backlight to adjust brightness through the terminal, which gave no errors but didn't change anything. Kernel parameters didn't make a difference either, if how I added them was correct (to the end of line starting with "linux", after "quiet"). My hardware is composed of an Intel i5 1.4GHz processor, Intel 2nd Gen. Core Processor Family GPU (this is what neofetch says), 4GB of RAM. It is a tablet PC (Samsung ATIV Pro 700T) with 60GB of storage.

Last edited by insciwetrust (2019-10-20 14:42:19)

seth · 2019-10-20 21:16:50

https://forum.xda-developers.com/showth … 02&page=25 and https://bugs.launchpad.net/ubuntu/+sour … ug/1380824 suggest the device needs "acpi_backlight=video"
https://bugzilla.kernel.org/show_bug.cgi?id=84561 supports that intel_backlight doesn't work w/ the entire device group.

Ensure you actually appended that to the commandline ("cat /proc/cmdline") and oc. then operate on /sys/class/backlight/acpi_video0, not on /sys/class/backlight/intel_backlight

pernia · 2019-10-21 02:11:01

just install brightnessctl form the official repos. do

man brightnessctl

to look at the man page to set brightness.

insciwetrust · 2019-10-25 15:43:33

pernia wrote:

just install brightnessctl form the official repos. do
man brightnessctl
to look at the man page to set brightness.

Commands seem to work, but they don't affect the brightness.

insciwetrust · 2019-10-25 15:50:16

seth wrote:

https://forum.xda-developers.com/showth … 02&page=25 and https://bugs.launchpad.net/ubuntu/+sour … ug/1380824 suggest the device needs "acpi_backlight=video"
https://bugzilla.kernel.org/show_bug.cgi?id=84561 supports that intel_backlight doesn't work w/ the entire device group.
Ensure you actually appended that to the commandline ("cat /proc/cmdline") and oc. then operate on /sys/class/backlight/acpi_video0, not on /sys/class/backlight/intel_backlight

Adding "acpi_backlight=video" to grub didn't work. Although I might have come one step closer to identifying the issue. The xfce power manager seems not to work as a whole, because even though I set the laptop to never go blank even on battery, it goes blank after 5 minutes.

seth · 2019-10-25 16:01:06

What do you mean by "didn't work"? Completely ignore xfce at this point.
Did you get an acpi_video0 device? What are the contents? Can you write into them?

insciwetrust · 2019-10-25 17:42:18

seth wrote:

What do you mean by "didn't work"? Completely ignore xfce at this point.
Did you get an acpi_video0 device? What are the contents? Can you write into them?

I added acpi_backlight=video to /etc/default/grub and it didn't change anything, acpi_video0 isn't listed in /sys/class/backlight and I wasn't able to adjust the brightness. I also tried to add it to /proc/cmdline but it gave "Input/Output Error."

Last edited by insciwetrust (2019-10-25 17:51:26)

seth · 2019-10-25 20:18:38

Just adding it to /etc/default/grub won't do anything and you cannot (trivially) edit the cmdline (and it would not do anything here anyway) - but I take it's not there, stressing that you did not actually alter the kernel parameters.

Re-read https://wiki.archlinux.org/index.php/Kernel_parameters …

Arch Linux

#1 2019-10-20 11:12:48

I can't manage display brightness (XFCE)

#2 2019-10-20 11:33:13

Re: I can't manage display brightness (XFCE)

#3 2019-10-20 12:31:08

Re: I can't manage display brightness (XFCE)

#4 2019-10-20 13:33:49

Re: I can't manage display brightness (XFCE)

#5 2019-10-20 13:50:34

Re: I can't manage display brightness (XFCE)

#6 2019-10-20 14:01:47

Re: I can't manage display brightness (XFCE)

#7 2019-10-20 14:41:28

Re: I can't manage display brightness (XFCE)

#8 2019-10-20 21:16:50

Re: I can't manage display brightness (XFCE)

#9 2019-10-21 02:11:01

Re: I can't manage display brightness (XFCE)

#10 2019-10-25 15:43:33

Re: I can't manage display brightness (XFCE)

#11 2019-10-25 15:50:16

Re: I can't manage display brightness (XFCE)

#12 2019-10-25 16:01:06

Re: I can't manage display brightness (XFCE)

#13 2019-10-25 17:42:18

Re: I can't manage display brightness (XFCE)

#14 2019-10-25 20:18:38

Re: I can't manage display brightness (XFCE)

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