[LAU] New User

Cesare Marilungo cesare at poeticstudios.com
Wed Mar 19 17:38:13 EDT 2008


Mark Knecht wrote:
> On Wed, Mar 19, 2008 at 1:52 PM, Cesare Marilungo
> <cesare at poeticstudios.com> 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.
>   
Yes, I remember that thread. But I thought my case would be addressable 
since the device are, at least, different. I also thought it should be 
quite common to have both an usb audio interface and an usb midi keyboard.
>    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.
>   
I'll try this. Thanks.
> Hope this helps,
> Mark
>
>
>   
All the best,

-c.



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