Google
  Web www.spinics.net

Re: PATCH: usb ehci debug port device gadget

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]


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


B and H Foto and Electronics Corp.

[Video for Linux]     [Linux Audio Users]     [Photo]     [Yosemite News]    [Yosemite Photos]    [Free Online Dating]     [Linux Kernel]     [Linux SCSI]     [XFree86]     [Devices]     [Old Linux USB Devel Archive]

Add to Google Powered by Linux