PowerMac G4 (Digital Audio)

Johannes Berg johannes at sipsolutions.net
Mon Dec 6 02:16:18 EST 2010

> Your snd-aoa seems to support PowerMac3,4. Is it really tested?

I used to add only IDs that some people tested, until most things worked
and I wholesale added all of the ones found in Darwin.

> The reason I'm asking: people are having problems with sound on that
> machine. Even snd-powermac didn't function, but I believe these
> patches have helped:
> http://ristosu.wippiespace.com/pub/alsa-tumbler-
> http://ristosu.wippiespace.com/pub/alsa-tumbler-

These patches are odd -- the first one adds something the second
removes? Am I supposed to look at the combination?

> The problem is that active state is inverted (i.e. 1) compared to
> other machines on inputs that detect a plug (and there is no
> audio-gpio-active-state in the device tree in gpio 15 and gpio16).
> Snd-powermac guessed wrong.
> How do you handle these in your code?

Well, there is gpio-feature and gpio-pmf right now. I suspect you can
get things working by adding some overrides to ftr_gpio_init(). I guess
you want something like

get_gpio("keywest-gpio1", NULL,

on the PowerMac4,3, and something else for the headphone ...

But frankly, it's been so long that it's not all making perfect sense to
me right now. If you send me a tarball of /proc/device-tree/ maybe I can
take a look -- just looked at my collection and I don't have that one.


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