Why does Ubuntu reset brightness settings at the loading screen?
Solution 1
With this guide you can save your brightness level on reboot/shutdown and bring it back after system startup. This does not affect system boot up time.
Make a text file in your home directory (or wherever else) to save the brightness level in it. Open up terminal by pressing Ctrl+Alt+T, then enter the following command:
sudo gedit /home/brightness
Save and exit gedit. Just let it be empty. Then type this command in terminal:
sudo gedit /etc/rc0.d/K99FixBrightness
And copy paste the following bash script into it:
#!/bin/bash
brightness=`cat /sys/class/backlight/acpi_video0/brightness`
echo $brightness > /home/brightness
exit 0
Then make it executable by entering: sudo chmod 644 /etc/rc0.d/K99FixBrightness
in terminal.
Rpeat above steps with rc6.d directory:
sudo gedit /etc/rc6.d/K99FixBrightness
Just so:
#!/bin/bash
brightness=`cat /sys/class/backlight/acpi_video0/brightness`
echo $brightness > /home/brightness
exit 0
Then make it executable by entering: sudo chmod 644 /etc/rc6.d/K99FixBrightness
in terminal.
Until now we set up the brightness level to be saved in /home/brightness before shutdown and reboot. One step to go! Enter the following command in terminal:
sudo gedit /etc/rc.local
Add this before the last line "exit 0":
brightness=`cat /home/brightness`
echo $brightness > /sys/class/backlight/acpi_video0/brightness
Save and exit gedit. Now with system startup the last brightness level will be loaded!
Done! :)
Solution 2
Have you tried the following?
Open Terminal (Press Ctrl+Alt+T) and type:
sudo gedit /etc/rc.local
Add this before the last line "exit 0":
echo 4 > /sys/class/backlight/acpi_video0/brightness
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Clairton Menezes
Not much to say. Just one more blissfully ignorant random user
Updated on September 18, 2022Comments
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Clairton Menezes over 1 year
Since I first installed Ubuntu 11.10, I noticed that volume and screen brightness get reset every time Ubuntu starts.
Why is this so? And what ways are there to keep brightness and volume levels after rebooting?
I have found some scripts that change the screen-brightness at login. But this is not a good solution since
- login is slower because it seems to wait until the screen brightness is at the level specified by the script. After entering the password I see the screen brightness go down gradually. Only after this is complete (~1 or 2 seconds) does the background disappear and Unity come up.
- The screenbrightness is not remembered but instead redefined at login. So it gets remembered for the first part of the boot, then set to MAX and then again re-set to normal value by the script. My boot process is as follows:
desired brightness: 2 (13,33%) / Max brightness: 15 (100%)- Bios / brightness: OK
- GRUB (violet background color, white text) / brightness: OK
- Ubuntu loading screen with the dots / brightness: MAX (win7 loads with OK-brightness)
- User Login / brightness: MAX
- Unity starts / brightness: OK
- It seems to be more like a temporary patch than a actual solution.
I'm looking for solutions that set the desired brightness permanently and consistently throughout the whole boot-process
After updating to 12.04 the behavior is the same.
I tried
-
setpci -s 02:00.0 F4.B=XX
The value of F4.B is always '0' regardless of what value I try to set it to (tried 0, ff, f, 5, etc) - The solution in this answer does not have any noticeable effect: Desktop doesn't remember brightness settings after a reboot
The variables at/sys/class/backlight/acpi_video0/
get changed if I use Fn+UP and Fn+DOWN
Any help is appreciated. Thanks!
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Admin over 10 yearsDid you found the answer to this question. I am getting the same problem please help.
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Admin over 10 years@MurtazaMunshi Unfortunately not. I still have the same issue.
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Admin over 10 yearsDamn....Why isn't anyone helping us over here.
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Clairton Menezes almost 12 yearsI edited /etc/rc.local but it has no effect ... I did a few reboots to make sure. The value of /sys/class/backlight/acpi_video0/brightness is always 15 after reboot.
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jasmines almost 12 yearsHave you other folders in
/sys/class/backlight/
besidesacpi_video0
? For example, I've got/sys/class/backlight/intel_backlight/brightness
too, and I would add alsoecho 4 > /sys/class/backlight/intel_backlight/brightness
to/etc/rc.local
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Clairton Menezes almost 12 yearsThank you for taking the time to look into this! I have just that one acpi_video0 folder nothing else. It has a litlle black arrow, though as if it were a shortcut?
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jasmines almost 12 yearsYes, it's a symlink. If you want to know the original folder, just type
ls -la /sys/class/backlight/
, but this won't help much.