[SeaBIOS] [PATCH v2 6/6] cbvga_set_mode: disable clearmem in windows x86 emulator.

[Patrick Rudolph]

On Mon, 2018-06-04 at 09:31 -0400, Kevin O'Connor wrote:
> On Mon, Jun 04, 2018 at 09:29:17AM +0200, Gerd Hoffmann wrote:
> > Signed-off-by: Gerd Hoffmann <kraxel at redhat.com>
> > ---
> >  vgasrc/cbvga.c | 10 +++++++++-
> >  1 file changed, 9 insertions(+), 1 deletion(-)
> > 
> > diff --git a/vgasrc/cbvga.c b/vgasrc/cbvga.c
> > index 3f16bee10c..f6ebe71242 100644
> > --- a/vgasrc/cbvga.c
> > +++ b/vgasrc/cbvga.c
> > @@ -192,8 +192,16 @@ int
> >  cbvga_set_mode(struct vgamode_s *vmode_g, int flags)
> >  {
> >      u8 emul = vmode_g == &CBemulinfo || GET_GLOBAL(CBmode) == 0x03;
> > +    /*
> > +     * The extra_stack flag is false when running in windows x86
> > +     * emulator, to avoid stack switching triggering bugs.  Using the
> > +     * same flag here to skip screen clearing, because the windows
> > +     * emulator seems to have problems to handle the int 1587 call
> > +     * too, and GO_MEMSET uses that.
> > +     */
> > +    u8 extra_stack = GET_BDA_EXT(flags) & BF_EXTRA_STACK;
> >      MASK_BDA_EXT(flags, BF_EMULATE_TEXT, emul ? BF_EMULATE_TEXT : 0);
> > -    if (!(flags & MF_NOCLEARMEM)) {
> > +    if (!(flags & MF_NOCLEARMEM) && extra_stack) {
> 
> FYI, extra_stack will only be true if CONFIG_VGA_ALLOCATE_EXTRA_STACK
> is set, but I guess that's okay.
> 
> Thanks, the series looks good to me.
> -Kevin
This commit breaks SeaBIOS' menu when used with coreboot's native
graphic init in text mode. Payloads are not affacted (tested NTLDR and
coreinfo).
Everything works fine with native graphic init in high resolution
framebuffer mode. I've got no debug log at hand, but I'll investigate
asap.
Tested on Lenovo T500 using libgfxinit with latest coreboot master.

Regards,
Patrick


> 
> _______________________________________________
> SeaBIOS mailing list
> SeaBIOS at seabios.org
> https://mail.coreboot.org/mailman/listinfo/seabios