My screen is just too bright. How can I adjust screen brightness? So far I tried the following:
- "Brightness and lock" settings doesn't work.
- Fn + F6 or F7 doesn't work.
- This doesn't work.
- This doesn't work too.
My Laptop is Toshiba Satelite L745
Unix & Linux Stack Exchange is a question and answer site for users of Linux, FreeBSD and other Un*x-like operating systems. It only takes a minute to sign up.Sign up to join this community
You can try
xrandr --verbose and look for a line with resolution like
LVDS1 connected 1024x600+0+0. The name of your display (
LVDS1 in this example) is needed here. Now you are ready to set brightness:
xrandr --output LVDS1 --brightness 0.4
xrandr sets software, not hardware brightness so you can exceed both upper and lower limits:
xrandr --output LVDS1 --brightness 1.7 xrandr --output LVDS1 --brightness -0.4 #negative value is also possible xrandr --output LVDS1 --brightness 1
Before doing this, I installed
firmware-linux-nonfree; I don't know whether that's affected anything.
xbrightness does not detect the backlight, you'll need to find the backlight file and manually set the backlight value yourself. Here's the process I used for my Toshiba Satellite C50-B-14Z:
wizzwizz4@mylaptop:~$ ls /sys/class/ ata_device devfreq i2c-adapter net scsi_device vc ata_link dma ieee80211 pci_bus scsi_disk video4linux ata_port dmi input phy scsi_generic vtconsole backlight drm iommu powercap scsi_host watchdog bdi firmware leds power_supply sound wmi block gpio mem ppdev spi_master bluetooth graphics memstick_host printer thermal bsg hidraw misc rfkill tpm devcoredump hwmon mmc_host rtc tty wizzwizz4@mylaptop:~$ ls /sys/class/backlight/ intel_backlight wizzwizz4@mylaptop:~$ ls /sys/class/backlight/intel_backlight/ actual_brightness brightness max_brightness subsystem uevent bl_power device power type
Now I've got the
/sys/class/backlight/intel_backlight/. I can read the value of this file:
wizzwizz4@mylaptop:~$ cat /sys/class/backlight/intel_backlight/brightness 3906
3906?! That's way more than the usual maximum of
15! Checking the
wizzwizz4@mylaptop:~$ cat /sys/class/backlight/intel_backlight/max_brightness 7812
That... makes more sense. So it's about half-brightness at the moment. Well, I like it quite dim, so I'll set it to
390 out of 7812:
wizzwizz4@mylaptop:~$ echo 390 | sudo tee /sys/class/backlight/intel_backlight/brightness 390
And the screen dimmed! Yay!
I found the screen brightness solution in a somewhat obscure article. My issue was my laptop couldn't remember brightness settings upon reboot. I'll post the link at the end of my answer.
All that was needed was to edit the file
/etc/rc.local and add one line.
First, back up the
If something goes wrong you can revert to the original file.
#!/bin/sh -e # # rc.local # # This script is executed at the end of each multiuser runlevel. # Make sure that the script will "exit 0" on success or any other # value on error. # # In order to enable or disable this script just change the execution # bits. # # By default this script does nothing. # screen brightness line added # it's to make the laptop remember settings at power up. echo 7 > /sys/class/backlight/acpi_video0/brightness exit 0
Note that I added the line
echo 7 > /sys/class/backlight/acpi_video0/brightness to my
In my Debian Wheezy setup, the value
echo 7 > … sets brightness midway between dark and bright. So 7 is perfect for me. Choose a value that suits you.
rc.local runs when you restart your machine.
Here's the link: Installing Ubuntu on Samsung 5 (SSD+HDD) | LinuxMeerkat
Scroll down the page to find how to change default screen brightness on a laptop.