On Mon, May 19, 2014 at 08:23:25PM +0100, David Woodhouse wrote:
On Wed, 2014-04-16 at 12:37 -0400, Kevin O'Connor wrote:
This is unfortunate. I can put a hack into seabios (not seavgabios) to use bigreal mode for int 1587 calls during option rom execution. But, it does raise the question of how many other callers expect the bios to not mess with the segment limits. (Though, to be honest, the only goal I have with coreboot native seavgabios is support for grub, lilo, syslinux, and maybe ntldr.)
Was there a conclusion to this? Did you eventually convince yourself that it could be *OK* for the video BIOS to trash the segment limits, for a limited set of boot targets?
Commit 6c68e7ad changed SeaBIOS to stay in bigreal mode for an int 1587 call that comes during option rom processing.
The coreboot native vga init stuff (vgasrc/cbvga.c) is basically a demonstration of SeaVGABIOS for cases where a "real" vgabios is not available or not desirable. As above, my goal for cbvga was only modern OSes.