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Re: PowerMac G4 (Digital Audio) sound

With your patch installed and my external speakers (I don't have a headphone set) plugged into the headphone jack on the back panel of the Powermac3,4 (G4 Silver), I downloaded
to my desktop (should be no copyright problems with that) and double-clicked it. The Grateful Dead playing "El Passo" came thru my external speakers and there was much dancing.

Running alsamixer showed:

Card: PowerMac Tumbler
Chip: PowerMac Tumbler
Master: OO 75<>75
Headphone: OO
Headphone: OO
Speaker: MM
Auto Mute: OO
DRC Range: 63

Unplugging the external speaker, the Grateful Dead came thru the PowerMac's internal speaker, and alsamixer showed:

Card: PowerMac Tumbler
Chip: PowerMac Tumbler
Master: OO 75<>75
Headphone: MM
Headphone: MM
Speaker: OO
Auto Mute: OO
DRC Range: 63

On 12/17/10 04:55, Risto Suominen wrote:
2010/12/17, Rick Thomas<rbthomas@pobox.com>:

But I'm having trouble figuring out what "headphone detection" is and
what it's supposed to be good for?

The idea is to play the sound through the headphones if they are
plugged-in, otherwise through the speakers. Snd-powermac has a
setting, auto mute, that affects this. It's on by default. I'm not
sure about snd-aoa.

1) Install a yaboot-fixed Squeeze-powerpc on my PowerMac3,4 machine.
2) Do the blacklist and /etc/modules changes and reboot.
(test snd-powermac)
3) download with wget your "alsa-modules" .deb; then install it with
"dpkg -i<...>.deb" then reboot again.
4) locate an mp3 file from somewhere?  (Got a favorite? So far as I can
tell, there aren't any useful ones included as part of the Debian
installation.)  Play it (how? -- does alsamixer do that?  I don't see
any controls for playing a file in the alsamixer screen...  Should I run
rhythmbox at the same time?)
That's one possibility, if you have installed the graphical
environment. Alsamixer cannot play. I've used mpg123 on command line.
The problem is to find an mp3 file. I've been using this short audio
file (I hope it's not someone's copyright):
It can be played with:
     cat tecbeat.au>  /dev/audio
(it needs OSS, modprobe snd-pcm-oss)
5) Then what?  Look for something (what?) to change as I plug a pair of
external speakers in and out the external-headphone jack?
Yes, M (mute) and O (on) in headphone and speaker columns.
6) Report the results to you and the powerpc mailinglist.
7) Do you want the same experiment done with the blacklist reversed?
Yes, please. To test snd-aoa. Actually, nothing needs to be
blacklisted or put into /etc/modules, in this case. The alsamixer
screen will be quite different.


ps. There is a wiki page about snd-powermac:
http://wiki.debian.org/PowerpcSoundcards .

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