* Markus Armbruster ([email protected]) wrote: > Gerd Hoffmann <[email protected]> writes: > > > Hi, > > > >> > Now let's review the three commands: > >> > > >> > * Gerd, why does "info usbhost" have no QMP equivalent? > > > > Works only when running qemu directly, in the libvirt sandbox qemu > > hasn't the permissions needed to scan the host usb bus so that would be > > rather pointless ... > > I don't think this meets either of the two criteria: > > * I meets "makes no sense in QMP" only if QMP implies "can't scan host > USB bus". Libvirt implies it, but QMP doesn't imply libvirt; it's its > most important, not its sole user. > > * It meets "of use only for human users" only if we're convinced it's of > no use to programs. > > To avoid speculation and endless arguments about what could or could > not be of use, we've always stuck to "when in doubt, assume it could > be of use". > > "Libvirt can't use it" falls short. > > "Any management application worth anything would deny QEMU the > capability to scan the USB host bus, and thus wouldn't be able to use > it" is exactly the argument we intended to avoid. > > QMP falling short of completeness in relatively unimportant ways like > this one isn't exactly terrible. The most serious effect is probably > serving as a bad example that leads to further arguments like this one. > These are well worth avoiding, though.
Markus: a) This is a separate discussion; info usbhost has been there for many years; this patch set doesn't change that. b) From HMP, if someone wants to add a command like 'info usbhost' to make their debugging of USB easy, then HMP is all for that and there's no way I'm going to require QMP implementations for a debug command. Dave -- Dr. David Alan Gilbert / [email protected] / Manchester, UK
