XFree86 can be run either from the console or side by side with Mac OS X's Aqua desktop in a full screen mode. In full screen mode with Aqua, when the X window system is active, it takes over the entire screen. You can switch back to the Mac OS X desktop by holding down Command-Option-A. This key combination can be changed in the user preferences. From the Mac OS X desktop, just click on the XDarwin icon in the floating switch window to switch back to the X window system. You can change this behavior in the user preferences so that clicking on the XDarwin icon in the Dock switches as well. The full screen cooperative mode with Aqua is known as Quartz mode, named after the Quartz 2D compositing engine used by Aqua.
From the console, the Darwin port of XFree86 uses the IOKit for device driver loading and discovery, rather than the XFree86 module loader. Because of this, the XFree86 configuration file is not used on Darwin or Mac OS X systems. The descriptions found elsewhere of devices supported by XFree86 for other operating systems also do not apply. Running XFree86 from the text console is known as IOKit mode.
XFree86 for Darwin or Mac OS X will work with any video card that
you have an IOKit driver for. If you are running Mac OS X, this
typically means any card that has been shipped by Apple. If a card works
for you with the Mac OS X GUI, it will work on the same machine with
XFree86. If you have a pure Darwin installation, you may need to download
additional third-party drivers from
Apple's Darwin site. IOKit drivers are typically installed in
Multi-button and scroll wheel mouse support works well with all USB mice that I have tested. I have done no testing with serial mice.