> That may not help. > A USB2 cable should still leave you using the xhci driver - just at the > lower speed.
> There is some 'magic' needed to hand over the port from ohci? to xhci > (which probably require correct parsing of ACPI data to work out which > usb2 port the xhci port is linked to). > If the port isn't handed over (ie no xhci support in the kernel) the > USB port should still run at USB2 speeds. > There are also significant differences between the xhci hardware. > Some of which are definitely bugs, some are probably documentedd bugs, > other are just the hardware engineers making life extremely difficult > for the software engineers. > For example: > The xhci controller supports arbitrary scatter gather except: > 1) The maximum fragment size is 64k. > 2) Fragments can't cross 64k address boundaries. > 3) The end of a ring segment must happen at the end of a USB packet. > David There are significant differences in hardware, not only for USB 3.0 and USB < 3.0, but other things as well, such as SCSI cards, and network adapters, both wired and wireless. When booted into my NetBSD-current (6.99.43) amd64 USB 2.0 stick installation, I plugged in an 8 GB USB 2.0 stick (Kingston Data Traveler) with an older 6.1_STABLE i386 installation to copy an xinitrc.icewm file. It was not recognized as a character device, wouldn't mount. So I made the copy by booting my FreeBSD 10.0-STABLE USB 3.0 Kingston Data Traveler installation, and that worked. Normally, that USB stick with NetBSD 6.1_STABLE i386 worked in NetBSD. Tom
