On Wed, Mar 04, 2015 at 02:31:08PM +0100, Juergen Gross wrote: > On 03/02/2015 12:39 PM, David Vrabel wrote: > >On 26/02/15 13:35, Juergen Gross wrote: > >>Introduces the Xen pvUSB backend. With pvUSB it is possible for a Xen > >>domU to communicate with a USB device assigned to that domU. The > >>communication is all done via the pvUSB backend in a driver domain > >>(usually Dom0) which is owner of the physical device. > > > >Why do we need a kernel usb backend instead of a user-space one using > >libusb? > > Good question. At a first glance libusb seems to offer most/all needed > interfaces. The main question is whether performance with libusb will > be okay. There will be one additional copy of the I/O data needed if > I've read the code in drivers/usb/core/devio.c correctly.
You can drive USB devices at line speed using libusb just fine. Try it out and see please, processors copy data _very_ fast these days. thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
