I can hear sound with internal speakers only if I plug headphones jack, without plugged jack, there's no sound at all; to listen thru headphones, I need to half-insert that jack and this leads to distortions; with h/phones jack plugged fully, no sound in phones, but sound in internal speaker. With the same half-plug, in OS X I head sound both via h/phones and internal speaker. Driver: snd-powermac. Audio card: Tumbler @ i2ca @ KeyLargo i2c (I can provide the full dump of OpenFirmware device tree).

As <gnubien> at #alsa @ irc.freenode.net suggested, I ran `alsamixer -c 0` and MM-ed 'Auto Mute'. After that, I can fully plug h/phones jack and enjoy full sounds w/o distortions but still can't get any sound when it's unplugged.

The result of running ./alsa-info.sh: Your ALSA information is located at http://www.alsa-project.org/db/?f=daac9e06cbe772222b90d7fba14c1a49a65b980c