usb dongle enumerate as mass storage device

[Dan Williams]

On Fri, 2008-11-21 at 01:49 +0100, Marcel Holtmann wrote:
> Hi Dan,
> 
> >>> If the mass-storage device is a "driver cd" thing, then the correct
> >>> method for "fixing" these devices is to write a small shim driver  
> >>> for
> >>> libusual that (by default) simply ejects the mass-storage device
> >>> whenever it's inserted, but allows override of this behavior using a
> >>> module parameter.  See the following Sierra TruInstall patches for  
> >>> how
> >>> this should happen:
> >>
> >> Oh, so that's how they do it? They wait for a eject command to  
> >> "change"
> >> personas and become their real device?
> >
> > Yep.  Some Option devices need to be sent the SCSI REZERO command
> > instead of a simple eject.  Firmware dependent method really.  The
> > Option 'hso' devices have:
> >
> > -  bDeviceClass            0 (Defined at Interface level)
> > -  bDeviceSubClass         0
> > -  bDeviceProtocol         0
> > +  bDeviceClass          255 Vendor Specific Class
> > +  bDeviceSubClass       255 Vendor Specific Subclass
> > +  bDeviceProtocol       255 Vendor Specific Protocol
> >
> > that's - == pre REZERO, + == post REZERO.  Same thing for the Huawei
> > modems.  So you can at least usually tell whether it's supposed to be
> > the modem or the mass-storage device on the first plug.
> >
> >> Out of curiosity, how would it work when the device is reconnected  
> >> and/or the
> >> system boots? The device requires another eject to switch into  
> >> being what it
> >> should be?
> >
> > Yep.  On Windows and Mac OS X, the custom drivers that the devices  
> > have
> > on their mass-storage CD thing probably handle this for you
> > automatically.  As should we under Linux :)
> 
> I was looking into that and actually I was really close to post  
> patches for the HSO and Novatel cards that I have. There is no point  
> in ever mounting these as storage devices since it just wastes time  
> and roundtrips through userspace. We could already be connected in  
> that 5-10 seconds. Anyhow, just got distracted by vacation :)

Yeah, it's been in my queue for about 2 - 3 weeks now, but was
distracted by NetworkManager 0.7.  We'll see who gets there first :P  As
I mentioned, my strategy was to just duplicate the Sierra patch except
for HSO.  I don't have any of the Novatel cards that have this problem
(though I might be able to get my hands on one), so I was going to do
that later.  Huawei would be another good one to target, though they
seem to be somewhat active upstream.

Dan