With vga=775 on the Linux command line a first boot of the VM running
Linux works fine. After a warm reboot it crashes during Linux boot.
Before that, valgrind points out bad memory write to console
surface. The VGA code is not aware that virtio-gpu got a message
surface scanout when the display is disabled. Let's reset VGA graphic
mode when it is the case, so that a new display surface is created
when doing further VGA operations.
https://bugs.launchpad.net/qemu/+bug/1784900/
Reported-by: Stefan Berger <address@hidden>
Signed-off-by: Marc-André Lureau <address@hidden>