the mechanism of USB hotplug

[M. Warner Losh]

In message: <87ab37ab0512012209j1a80a3f8l2ee36567f5fbe04e at mail.gmail.com>
            kylin <fierykylin at gmail.com> writes:
: sir :
:    I am now working on the pci e hotplug of freebsd ,and reading code
: of the relative part in linux.
: i have never touch the field of USB .
: now i wonder the mechanism of USB hotplug and the scsi hotplug .
: in linux and my working on freebsd ,there r specail mechanism to
: waiting for the hotplug event ,and the IRQ and MEM IO resource
: allocation is complex .
: i am fresh to the USB and the even complex SCSI driver arch , could u
: give me some advise ?

All FreeBSD devices use devd.  Unlike Linux, FreeBSD's generic device
architecture means that all busses automatically support hot plugging
hooks.

Warner