Re: [Qemu-devel] [PATCH v2 0/3] seabios: add serial console support

[Gerd Hoffmann]

On Di, 2016-07-05 at 09:06 +0100, Daniel P. Berrange wrote:
> On Mon, Jul 04, 2016 at 10:39:51PM +0200, Gerd Hoffmann wrote:
> >   Hi,
> > 
> > Next round of patches.  Changes:
> > 
> >  * Moved it all to a new sercon.c file.
> >  * Code maps cp437 to utf8 now, giving a much nicer display.  Compare
> >    "Use the ↑ and ↓ keys to change the selection." (this series) with
> >    "Use the ^ and v keys to change the selection." (sgabios)  ;-)
> >  * Simplified keyboard code, using enqueue_key now.
> >  * Restructed code, to cleanup things and to address review comments.
> 
> Currently libvirt has an option to turn on serial console support
> for the BIOS. When this is set it adds the sga device. How will
> libvirt know when seabios has this feature built-in, and thus does
> not need to add the sga device ? 

Current code activates the serial console (unconditionally) in case no
vga is present.  I want also support output on both vga and serial
console, but code for the later isn't there yet.

What the final default behavior will be is not clear yet.  Not enabled?
Enabled in case no VGA is present?  Enabled unconditionally (simliar to
ovmf)?

Likewise it is not clear yet how we'll go enable/disable this.

One option would be to continue using sgabios.bin in fw_cfg.  But
instead of loading and executing it activate the build-in serial console
if we find the file.  That would make the switch completely transparent
to upper layers.  But it is quite hackish of course ...

Comments and ideas are welcome.

cheers,
  Gerd