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| |__ _ __ ___ ___| |_) | |__ / / |_| | |__
| __| '__/ _ \/ _ \ _ <| __| / /| _ | __|
| | | | | __/ __/ |_) | |____ / / | | | | |
|_| |_| \___|\___|____/|______/_/ |_| |_|_|
The free VBE/AF driver project, version 1.2
http://www.talula.demon.co.uk/freebe/
"The nice thing about standards is that
there are so many of them to choose from."
======================================
============ Introduction ============
======================================
VBE/AF is a low level driver interface for accessing graphics hardware.
It provides all the same features as VESA 3.0 (access to linear
framebuffer video memory, high speed protected mode bank switching, page
flipping, hardware scrolling, etc), and adds the ability to use 2D
hardware acceleration in an efficient and portable manner. An /AF driver
is provided as a disk file (vbeaf.drv), and contains clean 32 bit machine
code which can be called directly by a C program. If implemented
correctly, these drivers have the potential to be binary portable across
multiple operating systems, so the same driver file can be used from DOS,
Windows, Linux, etc.
FreeBE/AF is an attempt to implement free VBE/AF drivers on as many cards
as possible. This idea came about on the Allegro mailing list, due to the
need for a dynamically loadable driver structure that could support
hardware acceleration. VBE/AF seemed to fit the bill, and Allegro already
had support for the SciTech drivers, so it seemed like a good idea to
adopt this format for ourselves. The primary goal is to make these
drivers work with Allegro, so the emphasis will be on implementing the
functions that Allegro actually uses, but we encourage other developers
to join us in taking advantage of this excellent driver architecture.
This project currently provides fully accelerated drivers for a handful
of chipsets, plus a number of dumb framebuffer implementations based on
the video drivers from older versions of the Allegro library. It has also
defined a few extensions to the stock VBE/AF API, which allow Allegro
programs to use these drivers in a true protected mode environment
without having to resort to the nearptr hack, and provide a number of
hook functions that will be needed to remain compatible with future
generations of the SciTech drivers.
The current status of the VBE/AF standard is somewhat confused. It was
designed by SciTech Software (http://www.scitechsoft.com/), who provide
commercial VBE/AF drivers for a wide range of cards as part of their
Display Doctor package. It was originally going to be released as a VESA
standard, but the VESA people seriously messed this up by charging
exorbitant sums of $$$ for copies of the spec. As a result, very few
people bothered to support these drivers, and the FreeBE/AF project was
only made possible by the information available in the SciTech MGL
library source code, and the helpfulness of Kendall Bennett (the designer
of the spec) himself. Unfortunately SciTech have now abandoned VBE/AF
themselves, replacing it with an equivalent but non-public API called
Nucleus, which is only available under NDA. SciTech will continue to
provide VBE/AF drivers for the cards which they already support, but
will not adding any new ones in the future, so this project is now the
only active source of VBE/AF driver implementations.
At present, the Allegro (http://www.talula.demon.co.uk/allegro/) and MGL
(http://www.scitechsoft.com) libraries are the only major packages which
can take advantage of accelerated VBE/AF drivers. As such, this project
is starting to look more like a implementation of video drivers
specifically for the Allegro library, rather than a potential
industry-wide standard :-) But it doesn't have to be this way! VBE/AF is
technically an excellent design: efficient, easy to write and use, and
highly portable. If you are writing graphics code, and getting frustrated
by the many limitiations imposed by VESA, why not think about using
VBE/AF instead? Even better, if you have a card that our project doesn't
yet support, why not add a new driver for it? This can be a lot of fun,
and we would be delighted to offer any help or advice that you might need.
============================================
============ Supported Hardware ============
============================================
Not all VBE/AF drivers provide the complete set of possible features.
Some may be written in a 100% clean and portable manner, allowing them to
be used on any platform, but others make use of the video BIOS in order
to set the initial video mode: this makes them a lot easier to write, but
means that it can only be used under DOS. Some of the drivers, in
particular the ones based on the old Allegro library chipset support,
don't support any hardware accelerated drawing at all: these are still
usefull because they provide high speed protected mode bank switching and
can work around the bugs in some manufacturer's VESA implementations, but
are obviously not nearly as cool as a fully accelerated driver.
This table lists the currently available FreeBE/AF drivers, and what
features they each provide:
ATI 18800/28800
Uses BIOS
Banked modes only
Supports farptr extension
Dumb framebuffer
ATI mach64
Uses BIOS
Banked and linear modes
No FreeBE/AF extensions
Hardware accelerated
Avance Logic ALG-2101, ALG-2201, ALG-2228, ALG-2301, ALG-2302
Uses BIOS
Banked modes only
No FreeBE/AF extensions
Dumb framebuffer
Cirrus 54xx (not 546x). Should be ok with 5426, 5428, 7541, 7543
Uses BIOS
Banked and linear modes
No FreeBE/AF extensions
Hardware accelerated
Matrox Millenium, Mystique, Millenium II
Uses BIOS
Banked and linear modes
Supports farptr and config extensions
Hardware accelerated
NVidia Riva 128, TNT. Conflicts with Windows!
100% portable
Banked and linear modes
Supports config extension
Hardware accelerated
Paradise
Uses BIOS
Banked modes only
Supports farptr extension
Dumb framebuffer
S3
Uses BIOS
Banked modes only
Supports farptr extension
Hardware accelerated
Trident TGUI 9440. Doesn't work under Windows!
100% portable
Banked and linear modes
No FreeBE/AF extensions
Hardware accelerated
Trident
Uses BIOS
Banked modes only
Supports farptr extension
Dumb framebuffer
Tseng ET3000/ET4000/ET6000
Uses BIOS
Banked modes only
Supports farptr extension
Dumb framebuffer
Video-7
Uses BIOS
Banked modes only
Supports farptr extension
Dumb framebuffer
stub driver (for testing and development purposes only)
Uses BIOS
Banked and linear modes
Supports farptr and config extensions
Slow software emulation of hardware drawing functions
===================================
============ Copyright ============
===================================
As the name implies, FreeBE/AF is free. Both the driver binaries and
sources may be distributed and modified without restriction. If you find
any of this stuff useful, the best way to repay us is by writing a new
driver for a card that isn't currently supported.
Disclaimer: no warranty is provided with this software. We are not to be
held liable if it fries your monitor, eats your graphics card, or roasts
your motherboard.
=================================
============ Credits ============
=================================
The DRVGEN utility is based on the djgpp DXEGEN system, by Charles
Sandmann (sandmann@clio.rice.edu) and DJ Delorie (dj@delorie.com).
Linking/relocation system and ATI mach64 driver by Ove Kaaven
(ovek@arcticnet.no).
VBE/AF framework, stub driver, Matrox driver, NVidia driver, most of the
old Allegro chipset drivers, conversion from Allegro to VBE/AF format,
and installation program by Shawn Hargreaves (shawn@talula.demon.co.uk).
Cirrus 54x driver by Michal Mertl (mime@eunet.cz).
Trident TGUI 9440 driver by Salvador Eduardo Tropea (set-soft@usa.net).
Avance Logic driver by George Foot (george.foot@merton.oxford.ac.uk).
Fixes to the Cirrus 5446 MMIO routines by Keir Fraser (kaf24@cam.ac.uk).
Tseng ET6000 support by Ben Chauveau (bendomc@worldnet.fr).
Paradise driver by Francois Charton (deef@pobox.oleane.com).
Tseng ET4000 15/24 bit support by Marco Campinoti (marco@etruscan.li.it).
Trident driver improved by Mark Habersack (grendel@ananke.amu.edu.pl).
Video-7 fixes by Markus Oberhumer (markus.oberhumer@jk.uni-linz.ac.at).
S3 driver improved by Michael Bukin (M.A.Bukin@inp.nsk.su).
Video-7 driver by Peter Monks (Peter_Monks@australia.notes.pw.com).
S3 hardware acceleration by Michal Stencl (stenclpmd@ba.telecom.sk).
Website logo by Colin Walsh (cwalsh@nf.sympatico.ca).
More graphics hardware support by [insert your name here] :-)
VBE/AF itself is the brainchild of SciTech software, and in particular
Kendall Bennett (KendallB@scitechsoft.com).
The Video Electronics Standards Association does _not_ deserve any
mention here. The absurd prices they charge for copies of the /AF
specification have prevented it from being widely supported, and I think
this is a great pity. Long live freedom!
=================================
============ History ============
=================================
30 March, 1998 - v0.1.
First public release, containing an example driver implementation that
runs on top of VESA.
31 March, 1998 - v0.11.
Added support for multi-buffered modes.
5 April, 1998 - v0.2.
Added an accelerated Matrox driver.
8 April, 1998 - v0.3.
Added accelerated drivers for ATI mach64 and Cirrus 54x cards, plus
minor updates to the Matrox driver.
12 April, 1998 - v0.4.
Proper installation program, more drawing functions implemented by the
stub and Matrox drivers, improved ATI driver, compiled with PGCC for a
5% speed boost.
26 April, 1998 - v0.5.
More accelerated features in the Cirrus and ATI drivers. Fixed bugs in
the Matrox driver. Added an option to disable hardware emulation in
the stub driver, which produces a non-accelerated, dumb framebuffer
implementation. The init code will now politely fail any programs that
try to use VBE/AF 1.0 functions, rather than just crashing.
10 June, 1998 - v0.6.
Fixed scrolling problem on Millenium cards.
1 November, 1998 - v0.7.
Added drivers for Trident TGUI 9440 and Avance Logic cards, and
improved the build process.
14 December, 1998 - v0.8.
Bugfixes to the Matrox Millenium II and Cirrus drivers. Converted all
the old Allegro library chipset drivers into non-accelerated VBE/AF
format, adding support for ATI 18800/28800, Paradise, S3, Trident,
Tseng ET3000/ET4000/ET6000, and Video-7 boards. Designed and
implemented an API extension mechanism, providing the ability to use
these drivers in a true protected mode environment, a more rational
relocation scheme, and various hooks that will later be needed for
supporting the SciTech Nucleus drivers.
20 December, 1998 - v0.9.
Bugfixes. Added a config mechanism, allowing the install program to
optionally disable some features of a driver.
3 January, 1999 - v1.0
Bugfixes.
27 March, 1999 - v1.1
Added acceleration support to the S3 driver, plus some bugfixes.
27 June, 1999 - v1.2
Added driver for NVidia cards. Improved the PCI bus scanning code to
know about bridges to secondary devices (so it can locate AGP cards).
Minor bugfix to the Mach64 driver (it was using the wrong clip rect
for scrolling displays). Minor bugfix to the Matrox driver (it was
setting the wrong background color for the hardware cursor).