[linux-audio-user] Fullduplex on PPC hardware

Marijn P. Vriens mpv at tecnocimiento.cl
Wed Oct 13 13:59:04 EDT 2004

Hi all,

I need to use the soundcard of a Apple IMac and IBook in Fullduplex audio
mode. I installed kernel 2.6.8 and i am using snd-powermac as the audio

I have been trying with ohphone to see if fullduplex works. Unfortunately it
keeps saying: "Could not open sound device  - Check permissions or full duplex
capability." (even when running as root).

Now, Apple being Apple, and this being post 2000 hardware, I do not think that
the hardware is only half duplex (but i have no conformation one way or the
other). It makes more sense that it's the driver.

So my question is: Does anybody know the status of full-duplex support of
PowerPC hardware under linux? Do I need to give some special options when
inserting the module or patch the kernel? I read somewhere that you need to
enable 2 DMA channels for full-duplex support, does this have anything to do
with this problem?


Director Tecnológico Tecnocimiento.

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