freebsd stable - Jan 2014 - 9->10: USB device number changes

If you're going from FreeBSD 9 to 10, the attach order of USB devices
may change.

FreeBSD 9's GENERIC kernel has various USB drivers compiled in.  On
10, only a few core drivers remain in GENERIC and drivers for other
devices are loaded dynamically as kernel modules by devd(8).  As a
side effect, the attach order and thus the numbering may change.

Specifically, I have four ucom(4) adapters on a machine, a mix of
three uplcom(4) and one uftdi(4) device.  On FreeBSD 9, these used
to attach in the USB address order.  On 10, the uplcoms all attach
first, in address order, and the uftdi afterwards, so the corresponding
devices cuaU[0-3] have been reordered.

I just thought I'd mention it.

-- 
Christian "naddy" Weisgerber                          naddy at
mips.inka.de

On Sat, Jan 04, 2014 at 04:41:43PM +0000, Christian Weisgerber
wrote:
> If you're going from FreeBSD 9 to 10, the attach order of USB devices
> may change.
> 
> FreeBSD 9's GENERIC kernel has various USB drivers compiled in.  On
> 10, only a few core drivers remain in GENERIC and drivers for other
> devices are loaded dynamically as kernel modules by devd(8).  As a
> side effect, the attach order and thus the numbering may change.
> 
> Specifically, I have four ucom(4) adapters on a machine, a mix of
> three uplcom(4) and one uftdi(4) device.  On FreeBSD 9, these used
> to attach in the USB address order.  On 10, the uplcoms all attach
> first, in address order, and the uftdi afterwards, so the corresponding
> devices cuaU[0-3] have been reordered.
> 
> I just thought I'd mention it.
Can we wire down USB buses and devices like we can with CAM?

e.g. for CAM

hint.scbus.0.at="ahcich0"
hint.scbus.1.at="ahcich1"
hint.ada.0.at="scbus0"
hint.ada.1.at="scbus1"

(etc)

If not, it would be nice to have that feature.

Gary