Re: [Libusb-devel] error submitting URB: No such file or directory

[Tim R. <ti...@pr...>]

Jeremy Beker wrote:
> 	Thank you very much.  That seems to be it; I knew I was doing  
> something stupid.  Just to make sure I understand this then, I need  
> to be looking for the bEndpointAddress field in the Interface  
> Descriptor then?
>   

Well, you need to KNOW which endpoint you want.  Generalizing a bit,
most USB devices have exactly one configuration with exactly one
interface with exactly one alternate setting, so picking config[0] with
interface[0] with alternatesetting[0] for an unknown device is pretty
safe.  However, the pipe setups vary.  An interface can (and often does)
have several pipes.  For some devices, simple commands go through the
control pipe (endpoint 0).  For some devices, all commands are sent as
data through bulk pipes, which have arbitrary endpoint numbers.

If you are reverse engineering this, you may have to make some educated
guesses.

-- 
Tim Roberts, ti...@pr...
Providenza & Boekelheide, Inc.