[SeaBIOS] PC-BSD installer does not boot with 1.7.4 (bisected)

[Kevin O'Connor]

On Wed, Feb 05, 2014 at 11:04:42PM -0500, Kevin O'Connor wrote:
> On Wed, Feb 05, 2014 at 12:44:06PM -0500, Kevin O'Connor wrote:
> > On Tue, Feb 04, 2014 at 04:33:19PM +0400, Michael Tokarev wrote:
> > > We have a bugreport in debian, http://bugs.debian.org/737142,
> > > stating that PC-BSD does not work with seabios-1.7.4 anymore.
> > > 
> > > I digged in, and found out that it fails only with -vga std
> > > (cirrus works fine).  So I bisected the issue - only changing
> > > vgabios-stdvga.bin, and found this:
> [...]
> > This seems to be similar to the freebsd problem reported last year -
> > see:
> > http://lists.gnu.org/archive/html/qemu-stable/2013-03/msg00037.html
> [...]
> > (*) The best I can think of is to try and construct some hand crafted
> > assembler that can catch buggy x86emu emulators and force a failure..
> 
> I have put together some assember to try and run-time test for known
> broken versions of x86emu.  This patch to SeaVGABIOS does seem to
> catch the freebsd issue and in my tests it convinces freebsd to take a
> different approach.  The patch is a bit ugly though.

There hasn't been much comment, but I have pushed this patch to the
main seabios repo for now.

-Kevin