Re: [Qemu-devel] [PATCH 22/23] gtk: show a window for each graphical QemuConsole

[Anthony Liguori <aliguori@us.ibm.com>]

Gerd Hoffmann <kraxel@redhat.com> writes:

>   Hi,
>
>>>>> If so, we're going to need to model what the hardware actually
>>>>> does, which is that there's a single connection on the back
>>>>> of the box for a monitor, and it's guest software controllable
>>>>> which of the two display devices is routed to the connection...
>>>>
>>>> How does this work in 1.4?
>>>
>>> I guess the second display device was never ever shown anywhere?
>> 
>> Correct. We rely on "last display device wins" plus the fact this
>> happens to match up with the device Linux chooses for display.
>> This is obviously not great but up til now QEMU hasn't actually
>> supported multiple display devices so I haven't worried about it.
>
> Ok.
>
> I think the most sensible way to handle this is to implement the output
> routing device, make it own the (single) QemuConsole, and depending on
> the router state the one or the other display device is allowed to
> render to the QemuConsole.

Where does the switching happen in hardware?  Is this two devices with a
DVI port with a switch on it to have a single output port or it is
something more sophisticated where there are two memory regions and a
register is used to select which one is written out?

Regards,

Anthony Liguori