Re: USB gadget with drivers "on board"

From: Alan Stern
Date: Wed Apr 28 2010 - 11:59:14 EST


On Wed, 28 Apr 2010, [utf-8] MichaÅ? Nazarewicz wrote:

> So it will be enough to change the USB device class for the zeroth
> interface for udev to recognise the mass storage to be ejected? Note
> that I will use mass storage in the second mode as well.

No, you also have to go through a disconnect-reconnect cycle on the USB
bus. When you do, changing the bInterfaceClass value will be
sufficient to tell the kernel that the device needs to be
re-enumerated.

> Also, I think that it might be a good idea to make some "standardised"
> mechanism for all such devices so that a generic udev code could be
> written. Adding things to the descriptors may be difficult in a way,
> but maybe adding "[NoCD]" to the interface name would be enough.

I seriously doubt you'll be able to convince all the other
manufacturers to agree to a standardized convention for this.

Alan Stern

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