In ROM mode the global CapsLock state is controlled by the capslock ROM
by virtual KEY_CAPSLOCK events.
Guests are easily confused by spurious KEY_CAPSLOCK input events in
caps="rom" mode. These spurious events may reach the VMM if KEY_CAPSLOCK
is not pressed as first key in a combination and, therefore, is not
filtered as global key. We filter KEY_CAPSLOCK in ROM mode in the VMM
explicitly, but let it pass in non-ROM mode.
Per default RAW mode is used and CapsLock key events are sent unfiltered
to the guest.