how to set up xmonad and fglrx

1. delete /etc/X11/xorg.conf
2. reboot. X cannot start now.
run below as root
aticonfig --initial=dual-head --dtop=horizontal --overlay-on=1
a new xorg.conf should be created
3 run xmonad

xmonad with multi-head

4.1.1 xmonad does not detect my multi-head setup

If you've installed xmonad via Debian or Ubuntu packages, note that the current version of libghc6-x11-dev was not built with Xinerama support. You'll have to build the Haskell X11, xmonad, and xmonad-contrib packages from source until this issue is resolved.

If you've built from source, you may not have the Xinerama development files installed. Install them, then watch the configure output for X11. Look for the following lines:

   checking X11/extensions/Xinerama.h usability... yes
  checking X11/extensions/Xinerama.h presence... yes
  checking for X11/extensions/Xinerama.h... yes
 

Be sure to clean and rebuild xmonad after building and installing X11.

The following ghci commands can help investigate your Xinerama setup.

   :m + Graphics.X11.Xinerama Graphics.X11.Xlib.Display
  compiledWithXinerama
  openDisplay "" >>= getScreenInfo

compiledWithXinerama should give a Bool result, and getScreenInfo a list of screen Rectangles. Xlib error messages point to xorg configuration problems. Please check xorg.logs.

Though this is the kind of fix that shouldn't work, it nearly always does: If compiledWithXinerama returns True, try:

   runhaskell Setup.lhs clean
  runhaskell Setup.lhs configure --user --prefix=$HOME
  runhaskell Setup.lhs build
  runhaskell Setup.lhs install --user

for xmonad, and xmonad-contrib if you use it. Since xmonad 0.5, it is also sometimes necessary to

   xmonad --recompile

before you restart xmonad, so that the xmonad binary gets linked against the new X11 library.