blank external DVI on Thinkpad T40

Alex Deucher alexdeucher at
Wed Feb 25 13:50:52 PST 2009

On Wed, Feb 25, 2009 at 3:56 PM, Gilad Arnold <arnold at> wrote:
> On Wed, Feb 25, 2009 at 03:32:58PM -0500, Alex Deucher wrote:
>> Also, IIRC, the DVI port on the IBM docking station is only supposed
>> to support a max resolution of 1280x1204 or 1600x1200.  It might be a
>> limitation of DVI traces or connector in the docking station.
> I'm not sure. As I said, the DVI port used to work fine at 1900x1200
> prior to Xorg 1.3. Of course, back then the LVDS was disabled in the
> presence of an external DVI.

Perhaps the panel doesn't like the pll or the modeline?  Can you post
your xorg log and config somewhere?

>> Either of those should work.  You'll have to have another monitor
>> plugged in if you ignore the LVDS or it won't find any attached
>> monitors.
> The ignore option led to the aforementioned error, although I did have
> the external DVI monitor connected. I can try again with VGA-0 connected
> as well but suspect that the result will be the same.  The xrandr --off
> option did shutdown the LVDS, but did not help de-blanking the DVI...

IIRC, I vaguely recall the ignore option doesn't work right.
shouldn't matter anyway as turning off LVDS using xrandr does the same

> Has anyone had any positive experience with a similar setting? Perhaps
> it is a driver issue to start with? (fglrx does a better job with
> managing multiple displays?)

Multiple displays should work fine.  I think 1920x1200 on DVI worked
fine last time I tested on my rv250, but I can test again.


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