[xmonad] Problem with Multi-head setup

[wagnerdm at seas.upenn.edu]

Here is the way I understand it.  Likely some of the following  
statements will be subtly wrong, and I apologize in advance for  
spreading my misconceptions about X.

There are two distinct pieces of X called Xinerama.  One of the pieces  
is a set of library calls used for communicating the size and  
locations of physical screens in logical space within a single  
DISPLAY.  xmonad uses these library calls to break your physical  
screens into separate logical workspaces.  As such, the library called  
xinerama is required for multi-head support.

However, I understand that there are other ways of controlling  
multiple monitors, in particular running several different DISPLAYs  
under X, one for each screen.  You may of course do this; then you  
must start a separate xmonad instance for each DISPLAY.  There is  
currently no integration for this; i.e. no way to send windows from  
one DISPLAY to another (though I hear rumors that some window managers  
do have such capabilities).

Other than those two options, I am not familiar with any other way of  
driving multiple monitors.
Cheers,
~d

Quoting Eric Thomas <eric.l.m.thomas at gmail.com>:

> Sorry for the noob question, but why is xinerama required for xmonad to
> work?
> As I understand it, xinerama just makes your multi head setup appear as
> though there is one long screen.
> However, I like it when my screens are treated as two different desktops.
> Does xmonad not support this?
>
> Eric Thomas
>
>
>
> On Sat, Aug 22, 2009 at 4:55 PM, <wagnerdm at seas.upenn.edu> wrote:
>
>> Hi Eric,
>>
>> It sounds like you haven't got the Xinerama extension running; getting that
>> set up is not xmonad-specific.  There are many excellent tutorials on
>> setting up Xinerama on the web; Google should help here.  (For example, try
>> "setting up Xinerama", which pointed me to <
>> http://www.ibiblio.org/pub/Linux/docs/HOWTO/Xinerama-HOWTO>.)  It also
>> depends slightly on what graphics card you are using.  If you've got an
>> nvidia card with the proprietary nvidia drivers, check out the man pages for
>> nvidia-xconfig; other people here may have other suggestions for other
>> cards.
>>
>> Cheers,
>> ~d
>>
>>
>> Quoting Eric Thomas <eric.l.m.thomas at gmail.com>:
>>
>>  Hello,
>>>
>>> When attempting to setup xmonad on a dual setup, I cannot use the keyboard
>>> on the second monitor.
>>>
>>> The following command:
>>> ghc -e "Graphics.X11.openDisplay [] >>=
>>> Graphics.X11.Xinerama.getScreenInfo"
>>>
>>> generates this output:
>>> Xlib:  extension "XINERAMA" missing on display ":0.1".
>>> [Rectangle {rect_x = 0, rect_y = 0, rect_width = 1280, rect_height =
>>> 1024}]
>>>
>>> In the FAQ, its says to check my Xserver configuration, but I don't know
>>> what I need to check.
>>>
>>> Any help would be appreciated.
>>>
>>> Thanks,
>>>
>>> Eric
>>>
>>>
>>
>>
>