Re: mac99 SMP

[BALATON Zoltan]

On Tue, 4 Mar 2025, Jd Lyons wrote:
> Mac OS 9 the pointer seems to freeze on any SMP apps, Quicktime will 
> actually finish encoding MPEG2, but it has always locked the desktop to 
> only the task and that’s normal under OS 9 for QT MPEG2 encoder. It 
> seems to mouse freeze when it gets done and writes the final file to 
> disk, but the file is complete.
>
> Anything else, mouse freeze immediately on access to SMP. The system 
> does not fully crash, but becomes slow and somewhat unresponsive.
>
> The clock stops, and RTC is all screwed up.
>
> Likely a IRQ storm, I had not checked yet, but I’ll wait to see if the 
> Linux issue can be resolved, because that may fix this issue too.

Unlikely it will be fixed unless it can be debugged and since it seems we 
have no progress with that it might help if you try to identify the issue 
with MacOS. Maybe try enabling openpic logs/traces and try to find 
something that does not seem to work with SMP compared to one CPU or could 
cause interrupts to stop or falsely retrigger. There could be an issue 
with handling interrupts in the openpic model with multiple CPUs. This 
would need digging in a lot of logs and openpic docs to understand how it 
should work but I don't see an easier way to find the problem. It does not 
seem anybody here has any better idea or willing to dig into this so don't 
wait for others to solve your problem. If you can get MacOS people to help 
finding where it stops within MacOS then we would at least have an 
understanding of what actually happens so that would make it easier to 
find where it is in QEMU code so where it should be fixed. Without that 
we're in the dark.

Regards,
BALATON Zoltan