Re: [Mactel-linux-devel] macbook pro sound

[Christoph P. <cp...@ch...>]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Hi Dan!

> The modules all load appropriately and report all the correct  
> things.  The mixer works correctly, and 'aplay' works also.  With  
> external speakers plugged in to the notebook all seems fine.   
> However, whether external speakers are connected or disconnected,  
> no sound comes from the built-in speakers (they did work in OSX,  
> and they still produce the chime on start-up).
>
> Have I missed something in the configuration, or is the driver not  
> putting the output sound on some of the pins?

This seems to be a general problem with the Intel machines; it's the  
same situation under Windows on all three machines (iMac, MBP, Mini).  
My assumption is that there is a bit of code in the (OS X) driver  
that detects what is connected and switches the hardware  
appropriately. I'd suggest looking at the source of the OS X driver,  
but unfortunately it's no longer public. (So much for Apple's  
commitment to Open Source...)

The Sigmatel codec used by Apple should support 6 or 8 channels of  
analog audio. Maybe the internal speakers are connected to the rear  
channels or something? Can you play a 6-channel sound file through  
ALSA to see what happens?

- -chrisp

- -- 
chrisp a.k.a. Christoph Pfisterer   "A computer scientist is
cp...@ch... - http://chrisp.de      someone who fixes things
PGP key & geek code available        that aren't broken."

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.1 (Darwin)

iD8DBQFEG8ILr/EAHkwpC28RAgGrAKCkNcDUF5r3f1QoU2m09H5KsJpMZACgxqLz
HZ0xy98U4QyeMUuObOGk8gk=
=2BNr
-----END PGP SIGNATURE-----