'Zaphod' dual-head and mirroring

[Jamey Sharp]

On Wed, Jul 7, 2010 at 2:27 PM, Martin Langhoff
<martin.langhoff at gmail.com> wrote:
> Is there any way in current X.org to mirror across the two devices?
> (In practice we also need scaling for the external display -- but
> let's consider it optional.)
>
> Is there a way to get a ServerLayout/Screen stanza in xorg.conf that
> handles mirroring in zaphod mode?

I haven't tested this, but my reading of the code is that you should
be able to set the absolute position of the external screen to (0,0)
and turn on Xinerama, and everything ought to work. So you'd need
sections like these in xorg.conf:

Section "ServerFlags"
        Option "Xinerama" "true"
EndSection

Section "ServerLayout"
        Identifier   "layout"
        Screen       "internal" 0 0
        Screen       "external" 0 0
EndSection

I'm curious to hear whether that actually works: I've been wondering
whether Xinerama deals sanely with overlapping screens.

Jamey