External monitor can only "copy" laptop's built-in

[Aviram Jenik]

On Friday 21 May 2010 11:13:10 Dotan Cohen wrote:
> On 21 May 2010 19:42, Aviram Jenik <aviram at jenik.com> wrote:
> > Things to note: change the resolution/refresh rate of each screen to
> > their maximum (start with xrandr -q to see where you stand, and then
> > xrandr --output LVDS --mode YYYxZZZ). It also has switches to put one
> > screen on the right or left of the other, and it all happens immediately.
> > Of course, as Omer mentioned, make sure the virtual display settings are
> > big enough for (1680+1680)x1050.
>
> This seems to be my problem: setting the virtual display size:
> ✈dcl:~$ xrandr --fb 3360x1050
> xrandr: screen cannot be larger than 1680x1680 (desired size 3360x1050)
> ✈dcl:~$ xrandr --fb 1680x2100
> xrandr: screen cannot be larger than 1680x1680 (desired size 1680x2100)
>

I don't think you can do it at run-time. It should be an xorg settings, but 
you're right that the latest ubuntus seem to ignore it. I've got no idea what 
configuration had my virtual screen set, but I remember setting it 
explicitely (until I did, I had similar results to what you're describing).


- Aviram