[ltp] volume button debian/ubuntu

Henrique de Moraes Holschuh linux-thinkpad@linux-thinkpad.org
Wed, 20 Feb 2008 02:49:12 -0300


On Wed, 20 Feb 2008, Lior Uzan wrote:
> I don't understand. What's so horrible about the mute button muting both the
> jack and the speakers?
> Sounds normal to me...

Mute?  Not too much, but it is not a proper default configuration on a
non-*61 ThinkPad (i.e. it is different from how Windows behaves, and also
from how the ThinkPad itself behaves before Linux loads).

But have you given any thoughs on what that does to the volume up/down
control (on a thinkpad with a full mixer, not a T61)?  The internal speakers
and headphone output gets completely out-of-sync from the AC97/HDA mixer
that drives the line-out output (only available in port replicators and
docks).

There is more: the firmware beep genearator, that warns you of a lot of
things (like battery alarms), is subject to the speaker/headphone mixer, but
NOT to the general mixer, and it is NOT present on the line-out connector...

The thinkpad mute/volume keys, before the *61, were never meant to be used
to control the general mixer.  In the *61, they are just keys, except for
"mute", and *in order to maintain the proper behaviour of a thinkpad volume
control*, the firmware traps volume up/down to unmute unless you give it the
OSI string "Linux"...

And you will get weirdness if you plug in an extrenal keyboard and use
volume/mute keys on that, etc.

I personally just map Fn+insert and Fn+end to KEY_VOLUME_UP and
KEY_VOLUME_DOWN, fn+pgdn to KEY_MUTE, and leave the the volume keys alone.
That way, I can control the two mixers from the keyboard, without any
issues.

That won't work on a *61, of course.

-- 
  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique Holschuh