Subject: Re: PMAG-F console driver woes
To: None <port-pmax@netbsd.org>
From: Henry R. Bent <henry.bent@oberlin.edu>
List: port-pmax
Date: 03/29/2002 11:27:20
Toru Nishimura wrote:
> 
> Although I can not provide any solution for you...
> 
> Henry R. Bent <henry.bent@oberlin.edu>asked;
> 
> > px0 at tc0 slot 1 offset 0x0: 3D, 5x2 stamp, 24 plane, 128KB SRAM
> >
> > Is the SRAM statement really correct?
> 
> I guess so.  The SRAM is used for i960 local memory as well as
> command storage which holds request/reply between CPU and i960.

Okay, that makes sense.  Still seems a tad on the small side, but I suppose
it's fine for what it has to do.

> 
> > I have 4 memory modules on the board,
> > so does that really mean they're only 32K each?
> 
> It sounds like PX video memory, which is independent from and inaccessible
> from CPU.

That's what I was talking about: the memory modules on the PMAG-F itself. 
Sorry for the confusion.

> 
> > But on to the bigger problem.  The console driver gets somehow out of sync
> > with scrolling lines.  For instance,
> 
> PX 2D/3D video card was sorta enginneered monster of that time.  It was a
> pretty complex device built with a lot of hardwares even though it was
> a product of  "(then-) maturing RISC age."   Andy might have solutions for > you.

Yeah, it does seem to be a little bit of overkill for standard graphics in X,
and I don't even use anything but the console most of the time :-)  Although
I'm being very tempted to put it in a machine with either Ultrix or OSF/1 and
see how the accelerated X server is.  I'm curious to see the speed of the 3D
acceleration provided by the i860 and how it (in my /260) stacks up to my SGI
Iris Indigo w/an XS24-Z board.

> 
> > Another quick ignorant question: how easy/hard would it be to have this driver
> > recognize that the card takes up three slots?  Isn't it using all 3 for I/O?
> > I mean so that it would say something like "px0 at tc0 slot 1 2 3" at bootup.
> 
> PX consumes a single TC option card _address range_ although it might
> consume 3 or 2 option card _physical space_.

Oh, okay.  I went over this again in my mind and it made a little more sense:
it's not like having the card in two slots is suddenly going to make the TC
bus operate at 50MHz :-P


-- 
Henry Bent                       henry.bent@oberlin.edu
Want the Stars Productions       http://www.wtsp.org