I was just talking to Michael Tsirkin on IRC about determining which devices accepted a "bus" option, and asked why this option doesn't show up in the output of "qemu -device $devname,?" (as happens for addr, etc). He said this is an old bug, and asked that I send mail to the list as a reminder that it should be fixed.
So here is the reminder email :-) (note that I don't currently have any plans to use such informational output in libvirt; mainly I was interested in seeing it when manually running the command, as an aid to figuring out the nature of each device and how they can be categorized.)
