Re: PowerBook 5xx instability fix.

[David Brownlee <abs%absd.org@localhost>]

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 :)

Good catch tho'!

David