Subject: Re: I think I figgered out why it's stopping.
To: Chris Mason <cmason@nando.net>
From: Allen Briggs <briggs@puma.macbsd.com>
List: port-mac68k
Date: 07/31/1996 23:44:31
> I really have no idea what the last three lines are supposed to do.  All I
> know is that portBits.baseAddr is the location of the bitmap of the current
> grafPort.  I'm not so sure that, if I didn't have a video card, this would
> actually exist.  Could QD be faking it, that is pointing to a bogus
> grafPort.bitmap, since there's no video hardware?

It will exist (I think), but what it points to?  No idea.  It is
probably 0 (0x00000000).

> How can we detect if this is the case and trap for it??

I think we need a different test for 32-bit mode (if there isn't another
one in there), and the kernel probably needs to be updated to deal with
it (although it's probably OK if you're using the serial console and
don't have the gray bars set).  Can you write some code to check it out
and see what that is when the video card isn't installed?  (like, write
it to a file or something)

Brian, does any other code assume the existence of a video device?

-allen

-- 
 Allen Briggs - end killing - briggs@macbsd.com ** MacBSD == NetBSD/mac68k **
   Where does all my time go?  <a href="http://www.netbsd.org/">Guess.</a>