On Tue, 22 Jun 2010, Greg KH wrote: > On Tue, Jun 22, 2010 at 03:08:33PM -0400, Alan Stern wrote: > > On Tue, 22 Jun 2010, stephane duverger wrote: > > > > > Hello, > > > > > > This is a patch that implements an USB EHCI Debug Device using the > > > Gadget API. It does make use of "u_serial" to provide userland access. > > > > Specifically, it emulates a Netchip debug device. However it's not > > clear to me why any emulation is needed at all. Why not just use a > > regular serial gadget as a debug device? > > You would need to emulate the ehci debug port connection in the gadget, > right? I didn't think the regular serial gadget did that, but I might > be totally wrong. I don't understand what you mean. The connection from the debug port to the gadget is a regular USB cable; it doesn't need to be emulated. I don't remember the details about how the Netchip debug device works. 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? 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
