As far as I understood CRTC 0 is disabled, because it is only capable of generating analog video signals. I'm using a HDMI monitor, which is controlled by CRTC 1. To use multihead (not clone), you have to connect a analog (VGA) and digital monitor (in my case). Each monitor will use one CRTC and each CRTC will show a different part of the same screen. With this in mind every active CRTC should be listed as "native Windows monitor".
Regards,
Patrick
Von: "Henri Verbeet" <hverbeet@gmail.com>
An: "Alexandre Julliard" <julliard@winehq.org>
Cc: "Patrick Rudolph" <siro@das-labor.org>, "wine-devel@winehq.org" <wine-devel@winehq.org>
Gesendet: 30. Juli 2012 21:47
Betreff: Re: winex11.drv: xrandr1.2 don't assume CRTC 0 is active

On 30 July 2012 20:13, Alexandre Julliard 
  wrote:
> This clearly needs a helper function.
>
I'm not sure if this really makes sense to begin with. CRTC 0 is
supposed to be the primary display. With proper multihead support we'd
be able to enumerate the other display as well, and change modes on
them etc., but I suspect disabling the primary display isn't going to
give very good results on native Windows either, except perhaps for
applications that have multihead support themselves.