Re: [Mesa3d-dev] What is the properly way to write a HW driver for Mesa

[Klaus N. <kniederk@MI.Uni-Koeln.DE>]

>
> We don't have a document which explicitly explains how to write a driver,
> unfortunately.  Probably the best approach is to use a recent driver, like the
> R200 as a model / starting point.
>
> Keep in mind that writing a hardware driver is complicated.  Even if there was
> a 'how-to' document, it wouldn't be easy.  That's the nature of the beast.
>
> We'll try to answer your questions though.  The DRI-devel list would be the
> best place to ask.
>
> -Brian
>

I guess the DRI-devel list would be a better place to write to, but lazy
as I am...

I was also interested in trying to help out with the hw-driver stuff, but
I think that the entry level is VERY high. Not only the skill to do these
things is high, but also the technical "problems":

Let me explain. When I started with the Mesa-software driver, things were
easy. I just had to download 2MB of source-code, I could set the
LD_LIBRARY_PATH-variable and then I could already start modifying things,
playing around with the stuff, mess everything up, and do "rm -rf Mesa"
and start from the beginning etc. It was difficult to understand how Mesa
worked, but it was easy to play with it.

When I tried to do hw-stuff, things were different. First I downloaded the
DRI-files, just to learn that I need the newest XFree-version (well, I had
read this, but I still hoped maybe it works with the XFree from my debian
distribution. Nope.). So I downloaded XFree and it did not compile, I
started to look at the configuration files etc., I wasted two weekends and
I stopped my effort. If it had worked, I probably would have deleted my
old XFree in the process. What I want to say, is that it is really
difficult to start the hw-development. I think, you basically need a
second machine, that you just use for XFree-programming. It's not that
these things encourage.

My question would be this: Can the embedded-hw-Mesa driver be used for
development with similar ease as the software Mesa driver. Say you change
something start the test program on the console and if it was wrong, you
just reboot and that's it...
Is it easy to later port these drivers back to the XFree-version?

Thanks

	Klaus