#Backlight/Brightness change does not work

21 messages · Page 1 of 1 (latest)

pearl vigil
#

I'm on an HP Omen Max 16 laptop with an Nvidia RTX 5070 and an integrated GPU. When I try to change the brightness (whether it be with the brightness control keys or changes to /sys/class/backlight which the brightness keys achieve as well), the actual backlight of my display (built-in laptop monitor) doesn't change.
So far I've tried:

  • No relevant kernel parameters: nvidia_wmi_ec_backlight in /sys/class/backlight
  • acpi_backlight=native: Intel_backlight and nvidia0 in the folder
  • acpi_backlight=video: acpi_video0 and acpi_video1 in the folder
  • acpi_backlight=vendor: nothing in the folder
  • nvidia.NVreg_EnableBacklightHandler=1: Same as no parameters
  • nvidia.NVreg_RegistryDwords=EnableBrightnessControl=1: Same as no parameters
    Worthy of note is the fact that before nvidia_wmi_ec_backlight was in /sys/class/backlight even before i installed the Nvidia drivers (and it did not work then either) and backlight does work if I switch to iGPU only from the UEFI setup (which is not what I want).
    I attached the outputs of dmesg | grep -i -e nvidia -e i915 -e acpi -e backlight and journalctl -b | grep -i -e nvidia -e i915 -e acpi -e backlight > journalctl_log without any of the relevant kernel parameters.
📎 dmesg_log 📎 journalctl_log
spring pollen
#

[Disclaimer]
Login as root can be dangerous and should only be done when strictly necessary

Have you tried login as root to change those hardware values? Sometimes when messing with hardware files you literally have to be root for changes try sudo -i and try those changes in /sys/class/ hopefully its just that. Otherwise if both the keyboard fn keys and changing the hw files values dont work Im not sure what else to do, the wiki entry on this mostly talks about configuring the HW files https://wiki.archlinux.org/title/Backlight They note On Nvidia Optimus laptops, the kernel parameter nomodeset can interfere with the ability to adjust the backlight. Which could apply to you, otherwise there are various packages that can adjust backlight but I feel like messing with the HW files would yield better results. Anyways, make sure you read the whole wiki article even though its a real snoozefest.

pearl vigil
#
  • /sys/class/ does change, whether I use echo X > doas tee /sys/class/backlight/Y, use the KDE brightness applet or use the brightness buttons, so unfortunately not that
  • I don't have nomodeset set
    Unfortunately this one is tough.
spring pollen
#

So the file gets written to and the changes does stick but in reality the display doesnt increase brightness so the problems remains?

pearl vigil
#

Exactly

spring pollen
#

you did ls /sys/class/backlight/acpi_video0/*brightness and confirmed that the brightness isnt capped like super low?

#

cat /sys/class/backlight/acpi_video0/max_brightness

pearl vigil
#

Nope, it's 100

spring pollen
#

Is there some kind of powersaving setting in KDE that overrides the hardware config?

#

I'd suspect maybe a rogue setting.

#

Otherwise your guesses are as good as mine. I dont wanna make you try every random fix on the wiki lol

I know people dislike AI a lot but if you use critical judgement it can help brainstorming, sometimes it suggest things I would not have thought about but be very careful it really likes suggesting drastic changes that can mess up your system.

Personally since you know your setup best I would try and see if some of the stuff on the wiki could apply to you.

#

Youre also not the first one to have backlight issues, last threads about this I dont recall them ever being solved. So if you do find what's up let us know here linuxgospel

pearl vigil
#

Yea I'm not letting go of this :3

pearl vigil
#

Blacklisting nvidia_wmi_ec_backlight and then loading it after I've landed into the DE maximizes the brightness.

spring pollen
#

Consider marking the post as

#

... solved

sinful perchBOT
#

#17680 📣 If there is nothing else that we can do for you, please close this thread by adding "[SOLVED]" to the title.

  • You can do this on desktop by clicking the three dots on the top right of the page, and pressing "Edit Post".
  • You can also do this on Android / iOS by long tapping your post in the text channel list, and tapping "Edit Post".

Your title should be like so: http://0x0.st/8Rt9.png
Thank you

spring pollen
#

If there is nothing else we can do for you.

pearl vigil
#

Oh no, it's definitely not solved yet

#

The brightness gets maximized but can't be adjusted further