Dual-head config broke with update to 1.4.2

Martin Cracauer cracauer at cons.org
Mon Feb 15 14:44:38 PST 2010

Alex Deucher wrote on Mon, Feb 15, 2010 at 05:35:14PM -0500: 
> On Mon, Feb 15, 2010 at 5:24 PM, Martin Cracauer <cracauer at cons.org> wrote:
> > Alex Deucher wrote on Mon, Feb 15, 2010 at 11:27:39AM -0500:
> >> On Mon, Feb 15, 2010 at 11:14 AM, Martin Cracauer <cracauer at cons.org> wrote:
> >> > Alex Deucher wrote on Mon, Feb 15, 2010 at 10:52:44AM -0500:
> >> >> On Sun, Feb 14, 2010 at 6:51 PM, Martin Cracauer <cracauer at cons.org> wrote:
> >> >> > I have a Thinkpad T41 with an internal LCD and a VGA out, using an
> >> >> > older Radeon chip and the radeon Xorg driver. ?I have a display at the
> >> >> > VGA out and have configured dual-head via ServerLayout. ?This broke
> >> >> > with an update to Xorg 1.4.2.
> >> >> >
> >> >> > Short version:
> >> >> > - I seem to select the wrong output between LVDS (LCD), VGA, DVI and
> >> >> > ?TV. ?Instead of LVDS and VGA and I seem to get the (non-existent)
> >> >> > ?DVI and VGA. ?As a result, when X11 is up it seems that screen-0
> >> >> > ?disappeared and screen-1 (VGA) is now DISPLAY=:0.0. ?There is no
> >> >> > ?:0.1.
> >> > [...]
> >> >> Your best bet is to switch to using xrandr to configure your card:
> >> >> http://wiki.debian.org/XStrikeForce/HowToRandR12
> >> >> It will let you dynamically switch between single and multi-head.
> >> >
> >> > No, that doesn't work for me. ?I need classic dualhead with separate
> >> > $DISPLAY so that I have separate virtual desktop switching on each.
> >> >
> >> > I have seen that this works fine for the same Xorg version on other
> >> > computers not using the Radeon/ATI driver.
> >> >
> >> > So I reported it to the ATI driver list (assuming my subscription went
> >> > through).
> >>
> >> If you want to keep using zaphod mode, your best bet it to continue
> >> using the old version of the driver. ?New features like support for
> >> more than two outputs cause problems with zaphod mode.
> >
> > But I don't want more than two outputs.
> Most people want access to all the outputs supported by their cards.

At the same time? I don't understand.

Anyway, I think it should be rated as a bug that the Radeon drivers
triy, by default in a laptop, to use the DVI port that is only present
in the docking station.  Instead of the LCD panel built into the

It is still not clear to me whether I can use the old dual-screen
setup at all.  Do I just have a config problem or is this entirely
disabled in Xorg now?

> > All I want is my working pre-1.4.x setup with internal LCD and VGA
> > back. ?I hope this is a misunderstanding. ?I don't want any new
> > feature. ?Just my two old outputs just the way they were until I
> > upgraded Xorg.
> >
> > In case this is actually broken now, can I use an old driver in the
> > 1.4.x Xorg server or do I have to downgrade the whole server?
> You should be able to use the pre-xrandr1.2 driver (xf86-video-ati
> 6.6.3) with xserver 1.4.x.


> > so easily. ?Apart from the fact that it worked until recently with
> > your ATI driver and continues to work with other card's drivers the
> > model of work and setup is entirely different between classic
> > dual-head with two screens and xrandr. ?There's no easy way for me to
> > switch to any single-display dual-screen setup.
> What other recent open source drivers does it work with?  Most, if not
> all, xrandr 1.2 capable open source drivers have dropped zaphod
> support. 

The NVidia drivers in the same X11 server and I'm pretty sure another
notebook here with Intel G45 does it fine.  I can't check right now
which Xorg version that one has.

So what you are saying is that the official position of the Xorg
organization is that there will be no support for dual-head that has
separate screens anymore?

That there will be no way to have different virtual desktop switching
on the two screens? Just Microsoft Windows style big span screen

> I think radeon is the only one that even attempts to
> continue to support it anymore.  It still works it just doesn't
> provide a way to select which connectors you want to associate with
> each instance of the driver.  The number of zaphod users is relatively
> small and the amount of developer resources to support it is
> relatively high.  More people want to be able to use and dynamically
> switch between all their connectors than want to use zapod.

OK, but then as I said above, if the user can't pick the outputs it
seems a little counter-intuitive to select VGA and the DVI in the
not-present docking station as opposed to the Laptop's own LCD panel
which is present.

Can I hack this up in the source? If I kill any trace of the DVI port
would it come up with LCD and VGA?

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

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