There are a couple of methods that can be used to try to fix this.
1. Passing acpi_backlight=vendor to the kernel at boot
To try this temporarily, on boot at the grub screen, with the Mint option highlighted, press 'e' on your keyboard. If the Grub boot menu does not normally show up on boot, press and hold the 'shift' key whilst booting until it shows. On this screen, navigate to just before it says 'quiet splash' and type
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acpi_backlight=vendor
Try the brightness controls again and see if it works:
- If it does then keep reading to make them permanent
- If it doesn't, try method 2 before rebooting, the commands you already put in will be forgotten on next boot
To make it permanent in Mint 8 and after (with Grub2) follow the blue instructions, Mint 7 and before (with Grub legacy) follow the instructions in red. If you have upgraded from Mint 7, it is likely you will still have Grub legacy installed and should therefore follow the red instructions.
Mint 8+
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gksudo gedit /etc/default/grub
and inbetween the ""
write
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acpi_backlight=vendor
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sudo update-grub
Mint 7 and below
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gksudo gedit /boot/grub/menu.lst
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kernel /boot/vmlinuz-2.6.27-7-generic root=/dev/sda11 ro quiet splash
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kernel /boot/vmlinuz-2.6.27-7-generic root=/dev/sda11 ro acpi_backlight=vendor quiet splash
2. change the backlight with xbacklight
First install xbacklight
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sudo apt-get install xbacklight
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xbacklight -10
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xbacklight +10
- If it worked before rebooting but not after, follow the correct instructions in blue or red above and then continue reading down from here.
- If it worked after rebooting but not before, continue reading
- If it worked before and after reboot, continue reading.
- If nothing worked, its probably best to start a thread in the forum in a relevant section
The next step is to create a keyboard shortcut for them.
In the Mint menu, find the Keyboard Shortcuts application and click Add. In the name box, type Backlight Up and in the command box type xbacklight +10 and click Apply. Click the newly created shortcut in the Shortcut column and input the key combination that you want to use. There is a chance that the Fn+Button commands won't work, if so you may have to use Ctrl or Alt +the relevant button. Repeat this for turning down the backlight, but obviously with xbacklight -10 and a different key combination.
I welcome feedback, let me know if you spot a mistake or something is confusing. Also, if anyone has another method that worked for them that you think could be useful for other people, post it here or let me know.