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

[Kevin O'Connor]

On Tue, Feb 07, 2012 at 10:44:39AM +0200, Gleb Natapov wrote:
> On Mon, Feb 06, 2012 at 07:09:42PM -0500, Kevin O'Connor wrote:
> > Perhaps a semantic distinction, but I don't consider that to be a
> > seabios defect.
> > 
> Non optimal default. The default didn't change BTW, but it was config
> parameter before and we changed it for RHEL. Now config parameter is
> gone.

Config parameter moved from compile time to runtime.  But I agree it
is unfortunate that knowledge of that didn't get to the right people.

> > 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.)

So, compiling this into SeaBIOS doesn't seems like the right choice to
me.

-Kevin