Re: NetBSD 5.0 and SPARCstation 5 not a lucky combination

[Bill Roman <netbsd%songdog.eskimo.com@localhost>]

On Tue, 2009-07-28 at 00:13 -0400, Michael wrote:
> On Jul 27, 2009, at 9:18 PM, der Mouse wrote:
> 
> >>>> Could the lack of wscons to manage the sparc graphics devices be
> >>>> triggering the kind of unserialized register setting that der Mouse
> >>>> described as a possible cause of this effect?
> >>> Not directly, because that means that the kernel isn't scribbling on
> >>> the framebuffer to draw console text; rather, it's punting to the
> >>> PROM output routines.  At least, unless RASTERCONSOLE still exists
> >>> and you're using it.
> >> RASTERCONSOLE is what's set up in GENERIC for NetBSD/sparc 5.0.
> >
> > Oh, that makes it more interesting.  Then the console _is_ talking
> > directly to the framebuffer.
> >
> > _Lack of_ wscons is unlikely to cause problems, it seems to me.
> 
> The acceleration code is slightly different.
> 
> > wscons combined with RASTERCONSOLE, I don't know what that would do;
> 
> It would #error out
> 
> > I haven't looked at sparc wscons at all.  I wonder if the other  
> > observed cases
> > were all using RASTERCONSOLE?  If it's on by default, quite likely so;
> > perhaps that's where the bug is.
> 
> Probably, I dimly remember that the old rcons code draws at least the  
> cursor and maybe all text by software and uses the blitter only for  
> scrolling and rectangle fills.

Whew!  The last few days it's been too hot to even think about powering
up a SPARCstation in the house.

Now that it's cooled off a little, I've enabled ssh (to avoid console
problems) and built a kernel with wscons enabled (and a lot of stuff not
applicable to the SS5 disabled).  It seems to work just fine, no
problems with scrolling.

So, there's something different about what wscons and RASTERCONSOLE do
to a cg6.  That should at least give a clue... maybe I'll meditate on
the relevant source when it cools off again this evening.  But I bet
someone who knows more about this might have suggestions exactly where
to look, and where to find relevant information.