6cd65969da
Rather than returning ~0, return 0 for every register in case of failure mode. The '0' is better to indicate that there's no device there. It avoids SeaBIOS detecting a device and getting stuck on it trying to read and write its registers. Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>