Commit c388f408b5 added the possibility to list the display
backends using '-display help'. Since the 'none' backend is
is not implemented as a DisplayChangeListenerOps, it is not
registered to the dpys[] array with qemu_display_register(),
and is not listed in the help output.
This might be confusing, as we list it in the man page:
-display type
Select type of display to use. This option is a replacement for
the old style -sdl/-curses/... options. Valid values for type are
none
Do not display video output. The guest will still see an
emulated graphics card, but its output will not be displayed
to the QEMU user. This option differs from the -nographic
option in that it only affects what is done with video
output; -nographic also changes the destination of the serial
and parallel port data.
Fix by manually listing the special 'none' backend in the help.
Suggested-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 20200120192947.31613-1-philmd@redhat.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
a1e8853ed2