[Qemu-devel] usb: Move interrupt handling from poll to async handling

[Hans de Goede]

This patchsets move interrupt handling for usb-redir and usb-hid devices
over from polling to async handling. Together with a patch to allow
async stepdown in ehci when the periodic schedule only contains interrupt
queues, and a patch to allow usb-hid devices to connect to ehci, this
fixes the usb-tablet causing a crazy cpu load for idle guests.

With this patchset the cpuload for a fully idle vm with usb-tablet
is lowered from 20% to 2-3% (on my laptop).

Regards,

Hans