RE: WD90C24 Anyone?

On Tue, 7 Nov 2006, Chris Schumann wrote:
>> [mailto:[email protected]] On Behalf Of Tim Roberts
>> [email protected] wrote:
>>> I have an old ThinkPad 750P. It uses the WD90C24 chip, which was in
>>> the old svga driver.

>>> What would it take to port that to the new XFree86 code?
>> I'm not above
>>> writing assembly code or digging in here, I just don't know
>> where to
>>> start or how much effort it might take... swatting a fly or
>> eating an
>>> elephant?

>> Holy moly!  You have a whopping 1 megabyte of video RAM there.

>> Will it work with the VESA fb driver?  If not, then you might
>> as well give up.  I have the source code for their old
>> Windows 3.1 driver, and it is more than 76,000 lines of
>> 16-bit x86 assembler.  The blitter provided virtually no
>> acceleration, so you won't really be giving anything up to
>> use the fb driver.

> This machine didn't quite get the VESA in firmware. It was
> provided by a DOS TSR, which was required for the Win3.1 and
> Win95 drivers. I thought it was for use with VESA, but now I'm
> not sure.

> Anyway, I don't think it's a good idea to require a DOS TSR
> for video in Linux.

> There is source for this chip somewhere in the annals of X
> code. I think XFree86 supported it as late as 3.1.

3.3.6, actually.

> The only mode I've seen with modern distributions is 320x200x1.
> It's not pleasant.

> I'd also like to get the pen interface to work on it, but one
> step at a time! :)

> So what's that next step?

You can start with reading the DESIGN document included in the distribution, 
using the 3.3.6 pvga1 driver as a guide in filling in the blanks.

Marc.

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