In comp.os.linux.setup colin353 <colin353@gmail.com>:
> Hmm...

> I'm trying to get a xinerama dual-head setup working on my Dell
> Latitude D610 and an external LCD with the "radeon" driver.

[..]

> Relevant parts of my /etc/X11/xorg.conf include:

> Section "Device"
> Identifier "X3001"
> Driver "radeon"
> Option "AGPmode" "4"
> Option "MonitorLayout" "CRT,TMDS"
> Screen 0
> Option "DDCMode" "true"
> BusID "PCI:1:0:0"
> EndSection

> Section "Device"
> Identifier "X3002"
> Driver "radeon"

Tried the following already?

Option "MergedFB" "1"

[..]

> This may be totally unrelated, but I have a warning in my Xorg.0.log:

> (WW) RADEON(0): Failed to detect secondary monitor, MergedFB/Clone mode
> disabled

> Oddly, Radeon makes flawless DDC communication with the monitor to
> determine resolutions, refresh rates, etc. What's the deal with that?

> Has anyone had this kind of problem before? If not, is there an
> alternate solution to Xinerama + radeon that will support multiple
> resolutions on dual head?

Does it work with the same resolution at all? It might be you
have a general problem with your dual-head setup?

Though I don't used different resolution, as my dual-head
monitors are exactly the same and TFT, so they just run their
native resolution, from 'xdpyinfo'

dimensions: 2560x1024 pixels (764x302 millimeters)
resolution: 85x86 dots per inch

Both cards use the radeon driver, sadly 3D doesn't work with
Xinerama on Xfree86. I can however switch the resolution on each
of them independently through all configured modes with no
problems. I'd be surprised if this shouldn't work with xorg.

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Michael Heiming (X-PGP-Sig > GPG-Key ID: EDD27B94)
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