Subject: Re: Anyone got a PXG Turbo working with TCWSCONS?
To: Andrew Doran <ad@interlude.eu.org>
From: Matt Dainty <matt@bodgit-n-scarper.com>
List: port-alpha
Date: 03/16/2003 16:00:01
On Sun, Mar 16, 2003 at 01:17:52PM +0000, Andrew Doran wrote:
> On Sun, Mar 16, 2003 at 12:39:04PM +0000, Matt Dainty wrote:
> 
> > I've found the problem, in stic_reset():
> > 
> > ---8<---
> > /* Second PixelStamp */
> > if (yconfig > 0) {
> > 	si->si_stamp[0x100b0] = config | 8;
> > 	si->si_stamp[0x100b4] = 0;
> > }
> > ---8<---
> > 
> > Commenting this small block out stops the machine check, and the
> > hardware appears to work okay. I've now learnt not to trust what I see
> > on the monitor with the S3 switch flipped to serial. Console seems to
> > work okay, and colours all appear as they should. I'm tempted to see how
> > X behaves now...
> > 
> > Does this code error make any sense to you?
> 
> At a guess: it thinks there's a second PixelStamp chip, but there isn't.
> What does dmesg say for the board?

pxg0 at tc0 slot 4 offset 0x0: 24 plane, 5x2 stamp, 128kB SRAM

I'm fairly sure when I got this board, (25$ eBay job, it looked cool
:-), that it was advertised as 24-bit, having 3 PixelStamp engines, and a
96-plane Z buffer. From looking at the board, there are three large
chips with circular heatsinks, three BT459 RAMDACs, an Intel chip (i860
I now realise), 2 memory modules fixed to the board, and six further
memory modules that are removable, (They are marked as VSIMM). It takes
up all three of my available TurboChannel slots.  

A photo can be included if desired. I didn't have much luck finding
promotional material for these beasts so apart from what I can
physically see, I could very well have been fed moo poo as regards tech
specs.

> There's a server you can grab at the URL below. To get X working you
> might need to tweak this line:
> 
> 	yconfig = (modtype & 0x600) >> 9;
> 
> ... to read like this:
> 
> 	yconfig = 0;
> 
> But maybe not. Make sure your kernel has the INSECURE option set,
> and that you have one of these:
> 
> pelican$ ls -l /dev/stic0
> crw-------  1 root  wheel  68, 0 Apr 27  2002 /dev/stic0

Yup, I saw the comments regarding INSECURE with px and pxg, so I enabled
that in foresight. I haven't made any further changes to any source
apart from the necessary commenting out in stic_reset().

I've downloaded the X server and it works! Almost. Using just twm I
immediately see corruption on the window titlebars, and if I scroll the
contents, they slowly suffer from pixel rot. I've exported a Mozilla
from another (faster) machine, and it displays fine in all colours.

Matt