External monitor of Thinkpad W530

[Gordan Bobic]

On 12/02/2013 12:00, Roberto Ragusa wrote:
> On 02/12/2013 11:22 AM, Gordan Bobic wrote:
>> On 12/02/2013 09:42, Roberto Ragusa wrote:
>
>>> I worked out a solution (but it is not easy) where I drive the LCD with Intel
>>> and the external VGA with Nvidia.
>>> The secondary X server can be run and stopped indipendently, it is actually
>>> a good setup if you have to use a projector, because you have the LCD with your
>>> usual desktop and the VGA with just what you need to be shown.
>>>
>>> I described how I did it some time ago here.
>>
>> I'll try to find that, it sounds like exactly the sort of setup I am planning to use on my new system. The only downside I can see is that once you fire up the apps on the secondary X server you cannot drag the windows back to the primary.
>>
>> You could, however, create a conf file for multiple display adapters with different drivers on the same X server. Last time I used such a setup was circa RH9/RHEL3 (pre-Fedora, using Matrox Millenium and ATI Mach64 cards), but I don't see any reason why it wouldn't work (unless it is one of many things that got lobotomized over time for no good reason at all - but that's a whole different rant that I'm not going to go off on right now). Whether such a setup is "pluggable", i.e. will support adding/removing monitors/adapters/screens dynamically without a restart, I don't know - I never tried.
>
> It is pluggable. Not automatic, but you can switch the VGA on and off with no issues
> (including disabling Nvidia for power saving).
>
> As you have two X servers, you are right, you can't drag things across.
> But:
>
> 1) you can have two sessions for the same user (using different DEs,
> in my case KDE as primary and fluxbox as secondary), so you have access
> to all your files.

I'm interesting in a similar but slightly different use-case.

Say I have 2 monitors and to GPUs. The primary monitor/GPU is always on 
Linux on bare metal. The secondary GPU I want to dynamically switch 
between the host (with the running X server) and a KVM VGA passthrough 
guest. For example, drag all my windows to the primary monitor, fire up 
the VM, and have X gracefully lose the secondary GPU without a restart. 
And similarly in reverse, hot-add itself the GPU again when the VM 
terminates and stretch onto the second screen again.

Unfortunately, I haven't found a way to do that yet without a Xorg 
restart. Hence why your 2-Xorg solution with separate logins is 
appealing as a workaround with reasonable functionality.

> 2) If you have VNC activated on the secondary, you will "remote" control it
> from the primary. Very useful, you can jump with the mouse inside what
> is projected, do something, than jump back out.

Have you looked into Synergy for that. :)

> If you are interested search for:
> "Re: nvidia optimus tricks (was: F16 - Adding a second video card)"
> (24 July 2012)

Most interesting, I'll take a look at that.

Gordan