Re: PowerBook 5xx instability fix.

[Nat Sloss <nathanialsloss%yahoo.com.au@localhost>]

On Sat, 5 Apr 2025 05:08:13 David Brownlee wrote:
> On Thu, 3 Apr 2025 at 03:30, Nat Sloss <nathanialsloss%yahoo.com.au@localhost> wrote:
> > Sorry I'm mistaken - ascaudio(4) does NOT have issues on the PowerBook
> > 160 or 520/540.  Which I have tested it throughly on. - The audio MD
> > code does not modify the top of memory.
> > 
> > What I'm observing on the PowerBook 520 is that a portion of the top of
> > memory is being used by the hardare when audio fifos are
> > started.....This can only be observed when using the audio hardware on
> > the PowerBook 520/540.
> > 
> > It is not an issue with all macs but as I only have a small number of
> > machines to test with I cannot be certain as to which models are
> > affected.
> > 
> > And for the sake of an addiotional 7 pages (56kB) it ensures that the
> > system functions with an AUDIO kernel or GENERIC for all macs - should
> > include all macs I cannot test on too.
> > 
> > Unless people with differnent hardware were to test I'm unable to refine
> > this patch further :(
> 
> I think it seems reasonable to enable it for all mac68k systems by
> default, as "never crashing when the console bell beeps" trumps an
> extra 56K of memory (even on a limited memory PB140 :)
> 
> Is the issue avoided if audio devices are not configured into the
> kernel? If so it might be nice to conditionalise it on audio devices
> being defined at build time. It *could* be done at run time by
> defining it as an extra region which is only released if audio is not
> attached, but that seems like a lot of work for 56k :)

Thanks.  I'll definately change it  to only map out the extra memory if audio 
is enabled at boot time.

> 
> Good catch tho'!
> 
> David

Best regards and thanks for looking at this,

Nat