[alsa-devel] Support for USB-Audio devices with Multiple configurations?

Cameron Stone camerons.lists at cse.unsw.edu.au
Thu May 14 08:32:20 CEST 2009

I'm writing some firmware for a USB microphone array with multiple
configurations, and I'm wondering if it's possible to tell ALSA which
configuration to use in a module option or something (device_setup,

I've been looking through usbaudio.c in the kernel source
(2.6.28-11-generic from the ubuntu Jaunty package), and I can't find any
generic device configuration like that.

If this is not possible, does anyone have any recommendations on how to
implement this? I can imagine doing it using quirks for this particular
USB_ID, but this seems like a fairly generic type of capability, so I'd
like to make it general if possible.

If anyone is wondering *why* I want multiple configurations: it's for
bandwidth management. I have 8 channels, but I want to be able to sample
1 channel as fast as possible without wasting bandwidth on the other 7.
I couldn't figure out a way to do that with a single configurations.
Please let me know if you know one. ;-)


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