Subject: Re: NuBus video news
To: None <ivanenko@ctpa03.mit.edu>
From: None <briggs@puma.macbsd.com>
List: port-mac68k
Date: 10/20/1996 23:25:10
> Here is a piece of good news about NuBus video: I have the new version
> of the code!

Cool!  It sounds like you found a few things worth documenting very well
in the source code (SGetBlock and NewPtr/DisposePtr).

> I got the video interrupts working correctly. I had to comment out
> panic() call in macrom.c:jswapmmustopper() for that. This function is
> harmless, it is supposed to switch 24<->32 bit addressing, why the
> panic? 

Well, we can never be in 24-bit mode, and switching into 24-bit mode
would be bogus--NuBus is mapped differently in 24-bit mode.

> 2) I have to map NuBus space exactly as it is, to 0xF?000000. Why this
> space is mapped to kernel virtual space and not to its physical
> equivalent? 

Because I thought that I could get away with changing it and because it
seemed cleaner (to me) for it to be mapped as it is now.  It looks like
it's a definite lose for the hardcoded addresses in the cards' drivers,
though.  It should not be hard to change back.

> In the grf_mv.c:grfmv_intr() function, char 0 in put in
> slotbase[0xA0000]. Where did this address come from?

It came from taking apart the interrupt routine on the "Macintosh Video
Display Card" (I think that's what it was called) that we had on one
machine.  My Quadra 700's internal video requires a long 0 at 0xf980010c
and my Two-Page Display requires a char 0 at slotbase[0xa00000].  What
kind of card do you have?

Scott, would you like me to merge my (somewhat kludgy) code in for this?
Or would you like to take a look at it, anyway?

-allen

-- 
              Allen Briggs - end killing - briggs@macbsd.com