2.) If you specify an USB device at the command line like -usbdevice host:0421:00ab and the device is not available (not plugged-in) when you start the guest, qemu segfaults.Haven't heard this one yet. I'm assuming it's a qdev interaction.
No. It is monitor_printf(NULL, ... Patch adding checks to usb-linux.c is on the qemu-devel list already.I've seen someone posted another patch which makes monitor_printf not barf on mon == NULL, which would fix the segfault too.
cheers, Gerd
