[Cialug] First free graphic adapter?
Renegade Muskrat
cialug@cialug.org
Fri, 22 Oct 2004 06:57:36 -0500
The text below was originally posted to LKML by Timothy Miller <miller
at techsource.com>. I got it after it was forwarded to
misc@openbsd.org. It describes the potential for the construction of a
new graphics adapter which is designed to be completely open, so there
will be no problems with drivers on open source operating systems. I
think it is a great idea, so i thought i'd forward it on since Mr.
Miller wants feedback. If you have answers to his specific questions,
it would probably make more sense to send them to Timothy Miller rather
than back to me. His address was given in the first sentence of this
message.
Here's the post :
I've brought this up the following subject before on LKML, but it
wasn't really resolved, and also, management at my company (Tech
Source) has only now started to warm up to my idea.
To begin with, I'm an ASIC/FPGA designer, as well as software
developer. My own projects here include X11 drivers (DDX modules) for
OpenWindows and XFree86, as well as the bulk of a graphics ASIC which
we use in our air traffic control systems. The point: we have a lot
of experience with graphics hardware and system software.
In short, what I have been proposing to my superiors is the development
of a graphics card specifically for open source systems. This means
full disclosure on all register interfaces so that no one has to deal
with anything closed source (BIOS included). The goal here is to
produce a graphics card which is a Free Software geek's dream in terms
of openness. If Tech Source (me being its avatar) can develop a
relationship with the Linux (and BSD) community, users and developers
can get a product that they want without being locked out by hardware
vendors that feel they have to protect every last little bit of IP
relating to their products. The EXPRESS PURPOSE of this product is to
be free-software-friendly.
I can produce more detail later, but first, some characteristics and
advantages of what I'm proposing:
- x86 BIOS/OpenBoot/OpenFirmware code under BSD and GPL license
- kernel drivers under BSD and GPL license
- X11 module under MIT license
- flashable PROM so that boot code can be added for more platforms
- usable as the console on any platform that can take a PCI, AGP, or
PCI-Express card
- downloadable schematic for the circuit board
- FPGA-based graphics engine so it's reprogrammable
- instructions on how to reprogram the FPGA, so it's hackable
- if we discontinue a product, we may release the Verilog code for the
FPGA - Since this is designed to be open-source-friendly, we want to
play by the rules of the open-source community.
- Tech Source would actively participate in the development and
maintenance of our own drivers.
- We will actually pay attention to problems and concerns raised by
users and developers.
- We won't be control-freaks.
The desired effects, for developers, of these characteristics would
include:
- The card "just works" with Linux because, maybe, the drivers would go
into main-line
- The drivers are not a debugging/tainting nightmare, since they are
open source
- The drivers are easy to work on, since you don't ever have to guess
about anything.
- The drivers are easy to debug because
(a) we document everything, and
(b) we'll talk to you.
- People will think it's cool and want to hack it.
The desired effect for end users:
- It just works.
- It's not a liability for system stability.
The reason this idea came up is because I, as a user of Linux, am often
frustrated by the lack of open-source support for graphics cards which
are not "pre-owned". Sure, SOME companies release specs so that we can
develop open source drivers, but those cards tend to be prohibitively
expensive, slower than their cheaper counterparts from ATI or nVidia,
and they STILL don't document the internals of the BIOS so that the
card can be ported to a non-x86 system. Furthermore, since all these
vendors focus exclusively on Windows, they don't give much help to
open source developers who may produce drivers which work but which
are sub-optimal in performance or stability. (Here, I have to make
the obligatory CYA statement that there is nothing wrong with their
business models -- it's just unfortunate for Linux users.)
By contrast, what _I_ want to produce would be supportable by both Tech
Source (mostly me), and also by anyone else who wants to hack it. I
would be one of the primary designers of the chip, so I would know it
inside and out. I would also be the primary driver developer, with the
help of others on LKML. So, I would be here to help, but hopefully,
the documentation would be clear enough (and the drivers I write,
complete enough) so that no one gets stuck having to guess or
reverse-engineer anything.
There are, however, some caveats. Tech Source is not willing to foot a
lot of development capital for this project. That means we can't spend
an excessive amount of time on developing a fully virtex shading
programmable 3D engine, and my superiors are not willing, as yet, to
give me sufficient funding to produce an ASIC. What this means is that
the design has to be small and simple and focus primarily on 2D
performance so that it can fit into an FPGA.
A 2D rendering engine is easy to parallelize, so although we can't
clock the FPGA design as fast as an ASIC design, we can easily
saturate a 128-bit DDR memory bus at, say, 200Mhz. A 3D rendering
engine, on the other hand, is a beast, and our performance will be
less than stellar (although certainly better than doing it all with
the host CPU). (If there IS sufficient demand, we would LOVE to
produce a
performance-competitive 3D chip, but keep in mind that that would be a
huge and expensive development effort, and would result in an expensive
product.)
The advantage of having this in an FPGA is that we can add features and
fix bugs as necessary, and provide a flash utility for everyone to use
to upgrade. You run the utility, cycle power, and you're set. This
way, if some kernel developer who is concerned about latency decides
that having an interrupt signal occur on some event that we don't
already cover, we can add the feature and supply a new bitfile in
relatively short order. You wouldn't have to buy a new card to
upgrade.
All of this, however, is a pipe-dream if it's not cost effective for
Tech Source. I have to make a very strong case to the CEO. I think
everyone at this company is excited about the IDEA of developing this
product. But we have no clue what the market is like. It's not worth
it to us to develop this if only a handful of kernel hackers are going
to buy it. We're guessing that some workstation and server vendors who
deal in Linux would like to resell this sort of product, because if our
drivers are in the mainline Linux kernel, it'll "just work". On the
other hand, maybe they're all perfectly happy with the graphics
controllers that come built into many Intel motherboards and have "good
enough" support.
The very fact that no other company has openly considered going to the
level of openness that I'm proposing might suggest that what I'm
proposing is completely out of touch with reality, because it just
can't be profitable.
So, here are some questions to answer:
(1) Would the sales volumes of this product be enough to make it worth
producing (ie. profitable)?
(2) How much would you be willing to pay for it?
(3) How do you feel about the choice of neglecting 3D performance as a
priority? How important is 3D performance? In what cases is it not?
(4) How much extra would you be willing to pay for excellent 3D
performance? (5) What's most important to you, performance, price, or
stability?
Feel free to insert your own questions and answers here. Remember, I'm
an engineer. My understanding of business is dilettantish at best.
I haven't worked out a complete design spec for this product. The
reason is that what we think people want and what people REALLY want
may not be congruent. If you have a good idea for a piece of
graphics
hardware which you think would be beneficial to the free software
community (and worth it for a company to produce), then Tech Source,
as a graphics company, might be willing to sell it.
Oh, and before you flame me, YES, I AM doing market research for Tech
Source here, but NO, I am not doing it at THEIR request. They told me
that if I wanted to do this, I would have to make a case for it, and
that's what I'm trying to do. This is MY idea, and I would personally
love to have a product like what I'm describing. I would also
personally very much enjoy WORKING on such a project, because then I
wouldn't have to do more boring stuff. There's a lot of selfishness
here on my part. But it's selfishess that I hope everyone else will
benefit from.
-- Dan
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"I'm still sane on three planets and two moons."
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Daniel Ramaley 3118 Cottage Grove Ave Apt 8
dramaley at spatulacity dot cx Des Moines, Iowa 50311
http://www.spatulacity.cx/ (515) 271-5233
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