On Wed, 2 Jan 2008, David Brownell wrote: > On Wednesday 02 January 2008, Alan Stern wrote: > > On Wed, 2 Jan 2008, Mike Frysinger wrote: > > > > > perhaps the code size is arguable as to whether it really matters. > > > the reason we want it is that we have a USB host controller that will > > > not work with USB hubs, so we want to make sure the system does not > > > attempt such things. (yes, such a USB host controller is retarded, > > > but the decision was out of our hands.) > > > > Just out of curiosity, how does a host controller manage to avoid > > working with external hubs? > > The transaction translators in external high speed hubs require > hosts to issue particular USB transactions. If the host controller > doesn't implement the that split transaction support, then it won't > be supporting external hubs.
So in theory one could connect a high-speed hub to such a host controller and expect it to communicate with high-speed devices. So long as no full- or low-speed devices are added there wouldn't be any split transactions. It wouldn't be USB-2.0 compliant but it should still work. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
