[lug] multi-monitor question - hw part

[Chip Atkinson]

I don't know what kind of Dell laptop/docking station you are using but
I'm using the configuration you describe right now.
I have a Dell Latitude D630 laptop plugged into the docking station that
came with it.  Into the docking station, I have two flat panel
monitors, one into the DVI and one into the VGA.  I'm using Ubuntu 10.04. 

To drive it, I am using the NVIDIA proprietary driver.  I can run the
NVIDIA configuration utility which detects the two monitors as well as the
laptop screen.  I can only run two of the three.  The weird thing is that
the xorg.conf file that the nvidia utility application writes out doesn't
select the two monitors so I have to re-select the two monitors.  It's not
really a problem for me since I don't take the laptop anywhere and I
hardly ever reboot.  When I do, it's < 1 minute to get it back working.

There was another guy here that had seemingly identical hardware but the
NVIDIA driver could not detect his monitors.  It always showed a generic
monitor and "TV".  Eventually he just had to swap out laptops and docking
stations, but he now has dual head off the docking station too.

Chip

On Mon, 6 Dec 2010, Davide Del Vento wrote:

> Hi,
> I have a (Dell) docking station for my laptop and the docking station
> has dual output (DVI & VGA). I'd love to have two monitors at the same
> time, and Ubuntu (Hardy) should support that: in fact, I get kind of
> what I want using the laptop screen (not exactly, but that is the sw
> part of the question I'll get to if I get to figure out the hw part).
> 
> Now, if I hook two monitors and turn both on before boot, only the DVI
> one gets used. Nothing helps the "detect display" button on the
> "screen resolution" application in system->preferences. Note that the
> same thing (when only a single monitor is hooked) shows the laptop
> display as mentioned above (with some glitches, but I can "see
> something" on both the laptop display and the other, external screen).
> With two external monitors, the VGA one looks dead.
> But it's not: if I keep the DVI monitor off, the VGA one is used.
> 
> CTRL-ALT-Fn ttys always work and stay on the only monitor that's being
> used for X (it'll be clear from the next sentence why this is
> relevant).
> 
> Now, if I turn the DVI monitor on during the boot process, but before
> X starts, the VGA monitor gets used until X login. Now, in this
> "setup" X works on the DVI, whereas CTRL-ALT-Fn ttys appear on the
> VGA. Nothing changes in the in system->preferences->screen resolution
> 
> The instruction manual of the docking station does not say anything
> besides that the two VGA and DVI connectors exist (technically, it
> doesn't even say that you can hook a monitor: if they were internally
> unwired the manual would be correct - do they wonder why nobody reads
> the instruction manuals?)
> 
> Question: do you think what I want to accomplish is hw-impossible? I
> mean, I verified that both VGA and DVI stacks (video card, cables and
> monitors) work, but why they cannot be on at the same time as one
> external monitor and the laptop screen can? I know, I could use the
> laptop screen as "second monitor", but that's a 13" so it's useless
> (I'm trying to get two 22").
> 
> Or do you think it is just a software issue, since the
> system->preferences->screen resolution gets confused? In fact, when I
> have the two monitors, it does show only one (with some hints that
> there might be another "behind", but no way to set it up, unlike in
> the laptop+only_one_external setup).
> 
> Has anybody succeeded in something similar (even without the docking
> station)? If so, can you recommend the distro, so that I can try it
> live and see if it changes anything (I think that the "live" option
> for the various distro has been one of the best innovations in OS
> ever).
> 
> Thanks a lot
> Davide
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