The highest VBE_DISPI_INDEX_ID version supported by QEMU is
VBE_DISPI_ID5. But currently QEMU only allows writing values up to
VBE_DISPI_ID4 to the VBE_DISPI_INDEX_ID register.
As a result of this when a lower version is written to this register and
later VBE_DISPI_ID5 is written back, reads from the register will
continue to report the lower version.
Indeed SeaBIOS is doing that during VGA initialization which causes
guests to always read VBE_DISPI_ID0 instead of the correct version.
Signed-off-by: Dennis Wölfing <denniswoelfing@gmx.de>
Message-Id: <20210607115303.228659-1-denniswoelfing@gmx.de>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
05ece98f96