[lug] multi-monitor question - hw part

[Maxwell Spangler]

On Mon, 2010-12-06 at 16:09 -0700, Davide Del Vento wrote:

> $ xrandr
> Screen 0: minimum 320 x 200, current 1680 x 1050, maximum 2048 x 2048
> VGA connected (normal left inverted right x axis y axis)

> LVDS connected 1280x800+0+0 (normal left inverted right x axis y axis)
> 261mm x 163mm

> TMDS-1 connected 1680x1050+0+0 (normal left inverted right x axis y
> axis) 473mm x 296mm

I think your problem is that your currently trying to get three monitors
working (the LCD display and two external monitors) ?

It's been my observation that unless you have special video hardware
most laptops can only handle two video outputs.  They're designed so one
signal goes to the laptop while the second signal goes to the video
port.  This allows the classic "presenter" style setup where you watch
your powerpoint slides on your laptop display while a projector displays
it on the big screen.

By plugging in a dock you may have three displays connected but the
video circuitry will only drive two.  The solution is to disable the
laptop display which then frees up two displays for the external
monitors.

I do this at work on HP gear and works surprisingly well.  VERY
comfortable and it's more screen space with two 20" 4:3 monitors than my
16:9 23" HP display at home.  

I'm on an HP Elitebook with an HP dock, two 20" HP monitors and using
Ubuntu 10.04 to power it.  I use the GUI front end on Ubuntu to xrandr
to manage it.

I'm still searching for cool Windows+Thinkpad ways of switching between
the dock and monitors to a single laptop display -- I can't just pull it
out of the dock and have it adjust.  Wish that was the case and I'd love
to hear others suggestions.

Davide, try disabling the laptop display and let us know what happens.
Also: Search the internets for people using the specific setup you've
got with Linux and see what they say.  This might be an issue that will
require model specific work to enable, but it should work, so keep
trying.


-- 
Maxwell Spangler
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