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

[Dotan Cohen]

On 21 May 2010 18:10, Omer Zak <w1 at zak.co.il> wrote:
> If you haven't done so, you need also to define a virtual screen size
> which is big enough to include both physical displays.
> You may want to have a look in man 1 xrandr.
>
> --- Omer
>

Thank you Omer, there was no indication in the KDE dialogue that was
even necessary.

Going through the manpage, it looks like I need the --fb flag.
However, it seems to automatically calculate the size if none is
given:

       --fb widthxheight
              Reconfigures the screen to the  specified  size.  All  configured
              monitors  must fit within this size. When this option is not pro‐
              vided, xrandr computes the smallest screen size  that  will  hold
              the  set  of  configured  outputs;  this option provides a way to
              override that behaviour.

In any case, the problem might be that my video driver doesn't support
such a large screen:
✈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)

How can I check if this is a driver issue, short of installing a
different driver?

-- 
Dotan Cohen

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http://what-is-what.com