[SeaBIOS] [PATCH] If an int 1587 call is made from an option rom, stay in bigreal mode.

Kevin O'Connor kevin at koconnor.net
Sun Apr 20 15:37:19 CEST 2014

On Sun, Apr 20, 2014 at 01:16:29AM +0200, Paul Menzel wrote:
> Am Samstag, den 19.04.2014, 12:30 -0400 schrieb Kevin O'Connor:
> > Modify the int 1587 handler to check if the POST phase is still
> > running.  If it is, use bigreal mode segment limits so that the caller
> > remains in bigreal mode when the 1587 handler completes.  This helps
> > with SeaVGABIOS' use of "direct" framebuffer accesses (an option rom
> > may attempt to display text during its option rom execution which can
> > cause SeaVGABIOS to make the int 1587 calls).
> Did you experience this or is that just a precaution? If you did
> experience this, could you please elaborate what hardware you used and
> which Option ROMs were executed?

Gerd reported the problem at:


This was experienced on QEMU with iPXE.  The problem is generic enough
that it could occur on any hardware and with any option rom that
writes to the screen.


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