Re: [Qemu-devel] [PATCH 0/4] vga: new display devices

[Gerd Hoffmann <kraxel@redhat.com>]

On Mi, 2014-03-12 at 14:55 +0100, Laszlo Ersek wrote:
> On 03/12/14 13:55, Gerd Hoffmann wrote:
> >   Hi,
> > 
> > This patch series adds new display devices.
> > 
> > Number one is secondary-vga.  That is identical to VGA (aka -vga std),
> > except that it doesn't occupy all the legacy vga stuff (ioports, memory
> > window @ 0xa0000), so you can have more than one of these in the system.
> > It has one pci memory bar for the framebuffer and one mmio bar for
> > registers.  OVMF can drive it.  Doesn't use it as console for some
> > reason, but initializes it and the linux kernel will see it as efifb.
> 
> My take is, due to the UEFI driver model, QemuVideoDxe is connected to
> this secondary VGA (and so another GOP instance is created). It's then
> probably up to GraphicsConsoleDxe to provide a SimpleTextOutput on top.
> My guess (without looking) is that this too happens, again thanks to the
> UEFI driver model.
> 
> What could be amiss is likely something in ConSplitterDxe, which accepts
> input from all consoles, and mirrors output to all of them as well.
> Perhaps it doesn't expect multiple GOPs.

Must be something else, I see this behavior with secondary-vga being the
only display device.  It prints a single line saying something along the
lines "display initialized", so SimpleTextOutput seems to be active.

cheers,
  Gerd