usb dongle enumerate as mass storage device

[Marcel Holtmann]

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 :)

Regards

Marcel