To enable the ‘Mute’ button on a Lenovo X200
(and probably some other notebooks as well)
it’s required to set an ACPI mode switch for the kernel.
Just open menu.lst in an editor
root@x200:~# nano /boot/grub/menu.lst
And add this switch: acpi_osi=”Linux”
kernel /boot/vmlinuz-2.6.31-14-generic root=UUID=kernel /boot/vmlinuz-2.6.31-14-generic root=UUID= … ro quiet splash acpi_osi="Linux"
After a reboot the ‘Mute’ button will be recognized instantly.
