On 9/26/07, Tobin Davis tdavis@dsl-only.net wrote:
The volume buttons should be supported by either acpi controls or keyboard settings. Try running showkey and seeing if they trigger keycodes. Once you have those, you could map them to a macro that adjusts volume through amixer. I know that there are applets for KDE to support the thinkpad keys, there may be others as well.
It's true; in particular, in Ubuntu, the thinkpad-keys binary from the hotkey-setup package watches for these key-events, and connects as a userspace input device to synthesize normal volumeup, volumedown and mute key events.
Unfortunately, that's not really how thinkpads work. =( They are fairly unique in that the hardware volume buttons actually control a separate hardware mixer independent of the sound chip itself, and there is no way I've seen in open source to prevent them from controlling that phantom mixer. So mapping them to also control the sound card's master mixer will eventually lead to a skew from expected results.
The phantom mixer can, however, be queried and changed through /dev/nvram and, in recent kernels, in /proc/acpi/ibm and some knobs in /sys. What I'm proposing is to expose the phantom mixer as an alsa mixer device.
-- Tobin Davis
Today's weirdness is tomorrow's reason why. -- Hunter S. Thompson