
mga_vid  -  MGA G200/G400 YUV Overlay kernel module

	Author:
		Aaron Holtzman <aholtzma@ess.engr.uvic.ca>, Oct 1999

	Contributions by:
		Fredrik Vraalsen <vraalsen@cs.uiuc.edu>
		Alan Cox <alan@lxorguk.ukuu.org.uk>

                       WARNING  -----  WARNING

This code messes with your video card and your xserver. It will probably
lock up your box, format your hard drive, and cause your brand new g400 
MAX to spout 6 inch flames. You have been warned.

                       WARNING  -----  WARNING

What does this code do?

	 mga_vid is a kernel module that utilitizes the Matrox g200/g400 video 
	 scaler/overlay unit to perform YUV->RGB colorspace conversion and
	 arbitrary video scaling.

	 mga_vid is also a monster hack.

How does mga_vid work?

	This kernel module sets up the BES (backend scaler) with approriate values
	based on parameters supplied via ioctl. It also maps a chunk of video
	memory into userspace via mmap. This memory is stolen from X (which may
	decide to write to it later). The application can then write image data
	directly to the frame buffer (if it knows the right padding, etc).


How do I know if mga_vid works on my system?

	There are test applications called mga_vid_test_g400 and mga_vid_test_g200.
	Use the appropriate one for your card. This test code should draw some
	nice 256x256 images for you if all is working well.
