xrandr dual-screen usability survery (Was: Dual-head config broke with update to 1.4.2)

Alex Deucher alexdeucher at gmail.com
Mon Feb 22 07:59:40 PST 2010

On Sun, Feb 21, 2010 at 2:26 PM, Martin Cracauer <cracauer at cons.org> wrote:
> Alex Deucher wrote on Wed, Feb 17, 2010 at 12:38:16PM -0500:
>> So fine, here's the yearly zaphod fix:
>> http://cgit.freedesktop.org/xorg/driver/xf86-video-ati/commit/?id=579cdcf9b4e38c791a497b747a055fc0a07d8dd6
> I'm afraid this doesn't quite do it.
> It corrects the mistake of detecting DVI (see log).
> But I still don't get dual screens, it still drops the internal LCD
> screen and I end up with one screen, mirroed.  That happens both with
> the fresh xorg.conf and with the xorg.conf that worked before with
> just the new option put in.
> Any ideas? Maybe I just overlooked some config option for a changed
> default?

I'll take a look today.

> conf/log/backported-patch here:
> http://www.cons.org/xorg-problem201002/firstpatch/
> I also noticed that the Xv extension on the VGA output is not
> functional in that mirrored mode.  The LCD displays the video picture
> but the VGA has a blue window.  This might be normal.

The video overlay one works one crtc at time.  You have to select
which one you want to use it with using the XV_CRTC Xv attribute (you
can use xvattr to change Xv attributes).  Textured video Xv support
has been available for a while now (several years) and that has no
head limitations, although if you are using an old version of the
driver it might be missing.  xvinfo will show you the available


> Martin
> --
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
> Martin Cracauer <cracauer at cons.org>   http://www.cons.org/cracauer/
> FreeBSD - where you want to go, today.      http://www.freebsd.org/

More information about the xorg mailing list