clone DVI output on an (ati) Inspiron 9300

[Louis-David Mitterrand <vindex+lists-debian-x@apartia.org>]

Hi,

Using the latest debian unstable packages, I'm trying to clone the 
display of my Dell Inspiron 9300 (Radeon Mobility M300) to its DVI 
output.

I succeeded in getting the DVI head to work with:

  Option      "MonitorLayout" "TMDS, AUTO"

but then the laptop's internal LCD blanks out. I tried many variations 
of that option without success.

In the debian packages I couldn't find any docs on the ati driver's 
various options.

Is there a specific xorg documentation package or README.ati somewhere?

Has someone been able to clone his screen on an external monitor through 
the DVI plug?

Thanks,