最近手边有一台 Acer 8481 装好 Ubuntu 10.10 后一开机觉得亮度太亮，系统调整亮度的功能似乎都没有作用，于是google 一下，发现这篇：Ubuntu 10.10 brightness problem in Acer Aspire 4741 照它所提供的做法：
sudo vi /etc/default/grub (自己习惯用vi)
把 GRUB_CMDLINE_LINUX="" 改成 GRUB_CMDLINE_LINUX="acpi_osi=Linux"
sudo update-grub
重开机
重开机后，我用 Fn + ← → 就可以调整亮度了。
Ubuntu 10.10 brightness problem in Acer Aspire 4741
To those who have problem with brightness configuration after installing Ubuntu 10.10 and you are using Acer Aspire 4741, here's a solution for you:
sudo gedit /etc/default/grub
Change the line GRUB_CMDLINE_LINUX="" into
GRUB_CMDLINE_LINUX="acpi_osi=Linux"
sudo update-grub
Restart your linux