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I've tried sooo many tutorials, forum instructions, etc, but nothing works at all. What might be the problem is that I can only edit the brightness file in /sys/class/backlight/nvidia_wmi_ec_backlight, while scale is stuck on unknown, max_brightness is stuck on 255, and sudo permissions are denied editing privelages to them. Please help me.
Hyprland environment
nvidia proprietary drivers, (iirc)
nvidia 3060 GPU
intel i5 chip
standard linux kernel
systemd boot
Edit: solved with https://bbs.archlinux.org/viewtopic.php?id=296205
NO idea how I missed this one for so long. Thanks for everyone in the comments trying to help me out though!
Last edited by Rainstripes (2025-07-01 04:41:52)
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This is generally speaking only for laptops, if you want this to manipulate an external monitor, said monitor has to support the ddc protocol and you'll need ddcutil https://wiki.archlinux.org/title/Displa … (E-)DDC/CI
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This is generally speaking only for laptops, if you want this to manipulate an external monitor, said monitor has to support the ddc protocol and you'll need ddcutil https://wiki.archlinux.org/title/Displa … (E-)DDC/CI
I mean, yeah, I'm not using any external display. I have arch installed on my laptop and the brightness won't change.
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What laptop and how sure are you that the nvidia gpu is driving your display?
xrandr -q
ls -l /sys/class/backlight/
sudo journalctl -b | curl -F 'file=@-' 0x0.st
What exact command are you trying that "sudo permissions are denied editing privelages to them" what exact command are you issuing? Have you seen https://wiki.archlinux.org/title/Backli … _utilities and checked e.g. brightnessctl or so.
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What laptop and how sure are you that the nvidia gpu is driving your display?
xrandr -q ls -l /sys/class/backlight/ sudo journalctl -b | curl -F 'file=@-' 0x0.st
What exact command are you trying that "sudo permissions are denied editing privelages to them" what exact command are you issuing? Have you seen https://wiki.archlinux.org/title/Backli … _utilities and checked e.g. brightnessctl or so.
1. I have an Acer Nitro laptop
2. Well that's the GPU I have, and /sys/class/backlight's directory has nvidia_wmi_ec_backlight
3. I'm running this:
cd sys/class/backlight/nvidia_wmi_ec_backlight
-which works fine, but then I run:
sudo echo 5 > actual_brightness
and it returns:
bash: actual_brightness: Permission denied
Even when I use sudo nano, I can't write it. It gives me [Error writing actual_brightness: Permission denied
Last edited by Rainstripes (2025-06-18 17:40:11)
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please post the output of these three commands, I highly doubt that your display is driven by nvidia, and see the note below.
Also general primer,
sudo echo 5 > brightness
elevates the echo but not the > which does the actual write, to properly do that use either of
echo 5 | sudo tee brightness
sudo bash -c 'echo 5 > brightness'
Last edited by V1del (2025-06-18 18:04:31)
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sudo echo 5 > actual_brightness
will never work.
You need to edit the 'brightness' file in that directory. Not actual_brightness or max_brightness.
I use 'brightnessctl' to manage the backlight on my laptop. This can be installed using pacman.
Last edited by 002445 (2025-06-18 18:03:54)
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sudo echo 5 > actual_brightness
will never work.
You need to edit the 'brightness' file in that directory. Not actual_brightness or max_brightness.
I use 'brightnessctl' to manage the backlight on my laptop. This can be installed using pacman.
I've already tried brighnessctl; no dice. As I said earlier, I can update the brightness file just fine, but my actual display's brightness doesn't change when I do. I just thought it was worth mentioning that sudo permissions weren't working on any of the other files, even though they don't change my brightness
Last edited by Rainstripes (2025-06-18 21:14:58)
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please post the output of these three commands, I highly doubt that your display is driven by nvidia, and see the note below.
Also general primer,
sudo echo 5 > brightness
elevates the echo but not the > which does the actual write, to properly do that use either of
echo 5 | sudo tee brightness sudo bash -c 'echo 5 > brightness'
Here's the output:
╰─ ❯❯ xrandr -q
ls -l /sys/class/backlight/
sudo journalctl -b | curl -F 'file=@-' 0x0.st
Screen 0: minimum 16 x 16, current 1920 x 1080, maximum 32767 x 32767
eDP-1 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 340mm x 190mm
1920x1080 143.88*+
1440x1080 143.80
1400x1050 143.89
1280x1024 143.79
1280x960 143.86
1152x864 143.92
1024x768 143.87
800x600 143.83
640x480 143.85
320x240 142.05
1680x1050 143.88
1440x900 143.86
1280x800 143.84
1152x720 143.77
960x600 143.72
928x580 143.50
800x500 143.68
768x480 143.69
720x480 143.85
640x400 143.37
320x200 141.40
1600x900 143.93
1368x768 143.77
1280x720 143.85
1024x576 143.91
864x486 143.63
720x400 143.88
640x350 143.57
lrwxrwxrwx - root 18 Jun 13:25 nvidia_wmi_ec_backlight -> ../../devices/pci0000:00/PNP0C14:01/wmi_bus/wmi_bus-PNP0C14:01/603E9613-EF25-4338-A3D0-C46177516DB7/backlight/nvidia_wmi_ec_backlight
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ls -l /sys/class/backlight/intel_backlight/
-r--r--r-- 1 root root 4096 Jun 19 08:19 actual_brightness
-rw-r--r-- 1 root root 4096 Jun 19 08:19 bl_power
-rw-rw-r-- 1 root video 4096 Jun 19 08:14 brightness
-r--r--r-- 1 root root 4096 Jun 19 08:14 max_brightness
-r--r--r-- 1 root root 4096 Jun 19 08:19 scale
-r--r--r-- 1 root root 4096 Jun 19 08:14 type
-rw-r--r-- 1 root root 4096 Jun 19 08:14 uevent
These are the permissions on my laptop. The reason you cannot change most files in that folder is that even root doesn't have write access. There is no issue with sudo or permissions from what you've told us.
You need to look into why the brightness doesn't change after changing the value in the 'brightness' file. I don't use an nvidia card so I am not familiar with that situation. Maybe there are some packages you need to install. I think there are open source and closed source drivers available for nvidia.
Last edited by 002445 (2025-06-19 06:25:28)
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I'm using the proprietary closed source ones. Are my drivers the problem then?
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