[alsa-devel] M-Audio Audiophile USB - Remaining issues

Thibault Le Meur Thibault.LeMeur at supelec.fr
Fri Jul 13 20:01:27 CEST 2007

>> It would be great if the one pcm device+subdevice was always linked to the
>> same interface (Analog or Digital)
>> Can anyone could point me to the piece of code that chooses the mapping
>> between the device physiscal interface and Alsa's pcm interface? I'll try to
>> see if I can fix this.
> In the case of usb-audio, it's a bit complicated.  The streams are
> assigned automatically per USB descriptions.  I think the easiest
> would be to mangle the PCM device number in alsa-lib USB-Audio.conf
> file.  Maybe Clemens can give a better hint.

Thanks for the tip... let me see have a look at this file....

Humm... at least there is something to change now :
USB-Audio.pcm.use_dmix {
	"AudioPhile" no    # uses big-endian 24-bit samples

==> This is not true anymore since if the device is used with  
device_setup=0x01 or 0x11, it supports S16_LE and thus dmix can be  
applied !

For the rest of the file, I definitely need Clemens' enlightenment ;-)

> The problem with multi plugin and JACK was fixed on 1.0.14.


>> 3- Have a user interface to switch device_setup modes
>> This may be the hardest to do and I don't think I've got the required skills
>> to do this. Anyway, I would realy appreciate any information (or existing
>> piece of code) about the following:
>> * how to write a user interface which interacts with the kernel module
>> * forcing a reinitialization of the snd-usb-audio module without
>> unprobing/reprobing the kernel module
> Well, the best would be to allow the driver to change the running mode
> on the fly without device_setup option.  But this seems requring
> fairly big change because of the current framework of the usb-audio
> driver.

I'm afraid this is beyond my skills :-(

Let's let this for the moment... Fixing point 1 seems more important.


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