Re: [Qemu-devel] [PATCH v2 0/8] qemu-ga: add support for Windows

[Gleb Natapov]

On Tue, Feb 07, 2012 at 07:35:34PM -0500, Kevin O'Connor wrote:
> > > In any case, I don't think this was addressed.  Gerd published a patch
> > > that can address this in qemu:
> > > http://www.seabios.org/pipermail/seabios/2012-January/002944.html
> > > 
> > Strictly speaking the patch is incorrect since it introduces the file
> > for all architectures, but I do not think qemu is the right place to
> > tune SeaBIOS defaults. I propose this patch instead:
> [...]
> >      // Load some config settings that impact VGA.
> >      EnforceChecksum = romfile_loadint("etc/optionroms-checksum", 1);
> > -    S3ResumeVgaInit = romfile_loadint("etc/s3-resume-vga-init", 0);
> > +    S3ResumeVgaInit = romfile_loadint("etc/s3-resume-vga-init", 
> > !CONFIG_COREBOOT);
> >      ScreenAndDebug = romfile_loadint("etc/screen-and-debug", 1);
> 
> I'm concerned about the VGA passthrough case.  (I know that's not
> common and has other issues, but I also know several people have been
> working with it.)  As near as I can tell, running the VGA rom on S3
> resume has as much chance of breaking things as helping things.  It's
> fine for the cirrus/bochsvga vgaroms that are totally under our
> control, but it'd be an open guess for any third-party code.  (Again,
> if someone has documentation to the contrary please let me know.)
> 
VGA passthrough does not work with QEMU without code changes. Whoever
works on it will have to provide etc/s3-resume-vga-init file with
appropriate value. My patch above does not remove run time selection, it
only changes the default.

> So, compiling this into SeaBIOS doesn't seems like the right choice to
> me.
> 
It is still run time selectable. I think it is best of both worlds.

--
                        Gleb.