[SeaBIOS] vga bios woes

Alex Williamson alex.williamson at redhat.com
Fri Jan 4 04:49:32 CET 2013

On Thu, 2013-01-03 at 20:57 -0500, Kevin O'Connor wrote:
> On Thu, Jan 03, 2013 at 06:41:35PM -0700, Alex Williamson wrote:
> > Thanks for filling in that piece of the puzzle for me.  If the above is
> > just a reporting problem, how do I fix it so I can actually step through
> > the rom?  Thanks,
> One other note - I think Darmawan may have been doing something
> similar with PCI rom debugging - you may wish to reach out to him.

Thanks for the connection.  For now the link Daniel provided has given
me enough to make progress.  It looks like this is a case where the VGA
bios manages to get the physical address of the device through a legacy
VGA register (0x3c3) and shoots itself by using that rather than the
emulated address found through config space.  I can kludge the offset
and get the VGA option rom to finish, but something is still wrong since
it doesn't trigger the monitor to sync.  Still digging.  Thanks for the


> On Sat, Nov 12, 2011 at 03:41:15PM +0700, Darmawan Salihun wrote:
> > I made a blogpost detailing the steps to debug PCI Option ROM with
> > Coreboot+SeaBIOS and a GDB-server-compatible debugger:
> >
> > http://bioshacking.blogspot.com/search/label/PCI%20Option%20ROM
> >
> > Hopefully would help those in need because it takes quite a while to
> > get it right.
> > Thanks to Kevin O'Connor for the helps :-)
> >
> > Regards,
> >
> > Darmawan

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