MP 1,1-5,1 Fix for 93% CPU, eventual hard crash on Mac Pro 1,1 Running Linux (Debian 13 / Ubuntu)

[ppinter1]

I worked with Claude AI to run down and fix the issue causing my 2006 macpro1,1 to periodically hard crash with Debian 13, getting back nearly an entire core, which was spinning madly servicing an unused Apple interrupt.

Write-up is attached.

 

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Another Pro Tip:

The Mac Pro 1,1 almost certainly doesn't support suspend/resume properly. A suspend can trigger a hard crash and reboot. The fix is straightforward, just don't enable suspend:

sudo systemctl mask sleep.target suspend.target hibernate.target hybrid-sleep.target