Hallo,

Alan Stern hat gesagt: // Alan Stern wrote:

> On Sun, 1 Feb 2004, Frank Barknecht wrote:
> 
> Maybe I'm to blame, since I wrote the code that rejects your device.  It 
> seemed like a good idea (and it still does) to alert people to problematic 
> devices rather than ignore any errors and consequently mess up the kernel.

I agree with you here. Of course this might mean, that I'll have to
sell my Quattro on Ebay. ;) But I'm testing lots of devices now and of
the 10 or so I'm done with, only the M-Audio failed on 2.6 (three
failed in general, but that's another story), so there *are*
alternatives.

> > How I understand what I read in the USB 1.1 specification, the
> > alternate setting has to be identified by a number, defaulting to
> > zero, which is in the range 0 to number of available settings minus 1.
> > Am I right to assume, that the Quattro's alternate setting "4" is
> > invalid, because it somehow exceeds this range?
> 
> That's right.  If you can boot a 2.4 kernel and look at either the
> /proc/bus/usb/devices file or else the output from lsusb, you should be
> able to see all the alternate settings for interface 1.  The error message
> you got means that there are no more than four of them, so they should be
> numbered from 0 to at most 3.

I did that now (I test on both kernels) and this is the output of 
"cat /proc/bus/usb/devices | grep Alt"

I:  If#= 0 Alt= 0 #EPs= 0 Cls=01(audio) Sub=01 Prot=00 Driver=snd-usb-audio
I:  If#= 1 Alt= 0 #EPs= 0 Cls=01(audio) Sub=02 Prot=00 Driver=snd-usb-audio
I:  If#= 1 Alt= 4 #EPs= 1 Cls=01(audio) Sub=02 Prot=00 Driver=snd-usb-audio
I:  If#= 2 Alt= 0 #EPs= 0 Cls=01(audio) Sub=02 Prot=00 Driver=snd-usb-audio
I:  If#= 2 Alt= 4 #EPs= 1 Cls=01(audio) Sub=02 Prot=00 Driver=snd-usb-audio
I:  If#= 3 Alt= 0 #EPs= 0 Cls=01(audio) Sub=01 Prot=00 Driver=snd-usb-audio
I:  If#= 4 Alt= 0 #EPs= 0 Cls=01(audio) Sub=02 Prot=00 Driver=snd-usb-audio
I:  If#= 4 Alt= 1 #EPs= 1 Cls=01(audio) Sub=02 Prot=00 Driver=snd-usb-audio
I:  If#= 4 Alt= 3 #EPs= 1 Cls=01(audio) Sub=02 Prot=00 Driver=snd-usb-audio
I:  If#= 4 Alt= 4 #EPs= 1 Cls=01(audio) Sub=02 Prot=00 Driver=snd-usb-audio
I:  If#= 5 Alt= 0 #EPs= 0 Cls=01(audio) Sub=02 Prot=00 Driver=snd-usb-audio
I:  If#= 5 Alt= 1 #EPs= 1 Cls=01(audio) Sub=02 Prot=00 Driver=snd-usb-audio
I:  If#= 5 Alt= 3 #EPs= 1 Cls=01(audio) Sub=02 Prot=00 Driver=snd-usb-audio
I:  If#= 5 Alt= 4 #EPs= 1 Cls=01(audio) Sub=02 Prot=00 Driver=snd-usb-audio
I:  If#= 6 Alt= 0 #EPs= 0 Cls=01(audio) Sub=01 Prot=00 Driver=snd-usb-audio
I:  If#= 7 Alt= 0 #EPs= 0 Cls=01(audio) Sub=02 Prot=00 Driver=snd-usb-audio
I:  If#= 7 Alt= 1 #EPs= 1 Cls=01(audio) Sub=02 Prot=00 Driver=snd-usb-audio
I:  If#= 7 Alt= 3 #EPs= 1 Cls=01(audio) Sub=02 Prot=00 Driver=snd-usb-audio
I:  If#= 7 Alt= 4 #EPs= 1 Cls=01(audio) Sub=02 Prot=00 Driver=snd-usb-audio
I:  If#= 8 Alt= 0 #EPs= 0 Cls=01(audio) Sub=02 Prot=00 Driver=snd-usb-audio
I:  If#= 8 Alt= 1 #EPs= 1 Cls=01(audio) Sub=02 Prot=00 Driver=snd-usb-audio
I:  If#= 8 Alt= 3 #EPs= 1 Cls=01(audio) Sub=02 Prot=00 Driver=snd-usb-audio
I:  If#= 8 Alt= 4 #EPs= 1 Cls=01(audio) Sub=02 Prot=00 Driver=snd-usb-audio
I:  If#= 9 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00 Driver=snd-usb-audio

Looks boring, but shows, that "Alt= 2" isn't used anywhere, so indeed
there are just 4 alternate settings.

> It _is_ a violation of the USB specification.  If M-Audio were to submit 
> their device for USB compliance testing, it would probably fail.  
> (Although I can't be certain of that because I don't know the details of 
> what they test for.)

I'll ask them for a comment. Thank you for your clarification and
eplanation.

ciao
-- 
 Frank Barknecht                               _ ______footils.org__


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