Re: [LAU] New User

On Wed, Mar 19, 2008 at 1:52 PM, Cesare Marilungo
<cesare@email-addr-hidden> wrote:
> >
> Hi Mark,
> what if you want to control the order of two different devices both usb
> (and so both handled by the snd-usb-audio module? In particular I have
> an usb audio interface and usb keyboard which is recognized as an audio
> device (even if it doesn't have audio functionalities). The order
> switches randomly at each reboot.
>
> Thanks in advance,
>
> -c.
>

Hi Cesare,
   Good to hear from you.

   This was the subject of another thread I asked on (I think) this
list a week or two ago. Apparently there is no way to do this for
cards using identical drivers. I had an opportunity to put together a
machine using 3 HDSP9652's but I needed to know that order of the
cards and ensure that every time I booted that the order wouldn't
change. The response I got was that Alsa cannot handle this.

   I did a little bit of study of how Windows does this for internal
cards. It appears that Windows pays attention to the resources the
device is using and keeps track of those. PCI bus and slot number. IRQ
assingment, etc. As loog as things don't change then it will comtinue
to use them the same way every day.

   For external devices it seems that the best way to do this in Linux
is though udev. Most external devices have a UUID of some type. If you
can identify the UUID and then build a udev rule it should work but
that's all way beyond my skill set.

Hope this helps,
Mark
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Received on Thu Mar 20 00:15:06 2008