Re: [Qemu-devel] Monitor and serial output window broken with SDL2

[BALATON Zoltan]

On Thu, 20 Dec 2018, Gerd Hoffmann wrote:
> On Wed, Dec 19, 2018 at 07:11:34PM +0100, BALATON Zoltan wrote:
> > On Wed, 19 Dec 2018, Daniel P. Berrangé wrote:
> > > On Tue, Dec 18, 2018 at 08:05:59PM +0100, BALATON Zoltan wrote:
> > > > On Tue, 18 Dec 2018, Daniel P. Berrangé wrote:
> > > > > I don't see any difference depending on whether I use Ctrl-Alt-3 before
> > > > > or after the yellow screen - both work as expected. The fact that you
> > > > > see a difference though does suggest that there's something odd being
> > > > > done in the ppc emulation that is in turn doing something bad to SDLs
> > > > > rendering with your graphics setup. I don't know what it could be though.
> > > >
> > > > OK thanks for checking this, at least it seems this is something that not
> > > > reproduces elsewhere so it's probably something specific to my setup. I may
> > > > try to debug this further when I'll have time.
> > >
> > > I think there's a good chance that this is still a bug in QEMU, so
> > > definitely still worth trying to debug what in your setup triggers
> > > it.
> >
> > Looks like Howard (cc'd) also has similar issue on Fedora 29 with NVidia
> > vendor driver although newer version than mine so the proprietary NVidia
> > driver seems to be a common point here. The difference is that for him the
> > monitor window seems to hijack the guest screen not the serial screen like
> > for me but this could be the same bug. I can't easily test with nouveau
> > driver now so that's all we could find out so far. Also having some output
> > on serial window seems to be relevant as this works before client starts if
> > I start with qemu-system-ppc -S but breaks after continue in monitor window.
> > qemu-system-x86_64 also does not show the problem but maybe because there's
> > no content in serial window there?
>
> qemu-system-x86_64 -machine graphics=off will make seabios print stuff
> to the serial line.

And with that it also shows the same problem so looks like this happens 
when something is output to serial and maybe with the NVidia vendor 
drivers on SDL2. I can't debug this more at the moment.

Regards,
BALATON Zoltan