Re: [Qemu-devel] [PATCH] vga: print friendly error message in case multiple vga devices are added

[Gerd Hoffmann <kraxel@redhat.com>]

On Mon, May 07, 2018 at 02:36:30PM +0100, Peter Maydell wrote:
> On 7 May 2018 at 13:11, Gerd Hoffmann <kraxel@redhat.com> wrote:
> >> This seems like a bit of an irritating reason to refuse to
> >> allow multiple VGA devices though, since we could make
> >> them work by having the vmstate be not-global.
> >
> > Multiple vga devices will also try to use the same isa vga
> > ports.  Seems that doesn't make qemu abort any more, which
> > used to happen in older versions.
> 
> Oh, good point. Shouldn't we be checking for that on
> some other thing than whether global_vmstate is set here,
> though? Otherwise it won't work consistently for the
> vga devices which pass 'false'.

The only one which passes global_vmstate == false is "-device
secondary-vga", and that does *not* register vga ioports (the
registers can be accessed via mmio pci bar though).

So, right now global_vmstate == "registers vga ioports", and
I don't expect that to change.

cheers,
  Gerd