On Tue, 22 Jun 2010, Greg KH wrote: > > Does it simply copy bytes from one port over to the other? At any > > rate, the EHCI spec doesn't say anything about how a debug device has > > to work; it only says how the debug port itself works. That port is > > theoretically capable of handling any high-speed device, subject to its > > length limitation (no packet can be longer than 8 bytes). > > > > Is that limitation the reason a special gadget driver is needed? > > The EHCI controller has some type of handshake happening for it to > determine that this really is a debug device, so that needs to be > emulated in the gadget somehow. Because of that, I would assume we need > some code to do so. The handshake, if any, is done by the driver and not the controller. The EHCI debug-port driver can always be updated to work with a wider range of debug devices. Would it make sense to provide a "debug gadget" module option for g_serial instead of creating a separate gadget driver? Or are the two so dissimilar that it wouldn't be worthwhile? Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
