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

[Laszlo Ersek]

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.

Laszlo