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

[Daniel P. Berrange]

On Tue, Jul 05, 2016 at 12:00:48PM +0200, Gerd Hoffmann wrote:
> 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)?

(Bitter) experiance in libvirt has shown us that magically enabling
things based on whether or not some other feature is enabled leads
to pain and suffering in the long term.

So from libvirt's POV, we would like an explicit command line flag
to turn on/off seabios serial console support, with no dependancy
on whether VGA is present or not.

Regards,
Daniel
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