Re: Multiple USB Endpoints

On Fri, Nov 16, 2007 at 01:59:16PM -0500, Alan Stern wrote:
> > On Fri, 16 Nov 2007, Martin Owens wrote:
> > As you can see it needs to be put in the second mode anyway, but there
> > is a third mode which is just the database stuff, without the mass
> > storage device. I believe the existing barry project is attempting to
> > claim all interfaces including the MSD one which is where it runs into
> > problems.

Hi,

I'm the lead developer of the Barry project.

I think the modes Martin is talking about is that the Blackberry Pearl,
and similar devices, can reboot itself and present 3 different
product ID's.

The most useful of these product ID's is 0004, which presents two
configurations: a Mass Storage, and a class 255 (the Database config).

The problem is that usb_storage sees the Mass Storage configuration,
and uses it.  When Barry wants to use the Database configuration,
there's a conflict.


> Okay, that seems straightforward enough.  The solution is (obviously) 
> to make the barry project avoid trying to claim the mass-storage 
> interface.
> 
> It shouldn't be hard to do.  You can tell which interface is 
> mass-storage by checking whether the bInterfaceClass value is 0x08.  If 
> it is, simply have the program skip over the interface.  The function 
> call you need to avoid is usb_claim_interface().

Barry doesn't use the Mass Storage configuration at all.  It uses
libusb to call set_configuration on the Database configuration, and then
usb_claim_interface on that.  If I comment out the claim_interface
call, I still get the error on set_configuration.

- Chris


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