System stalled with Areca ARC-1880i + MSI
Using an Areca ARC-1880i with MSI interrupt support on recent versions of DragonFly 3.1 causes disk throughput to slow to a crawl after a while.
Processes attempting to do IO are stuck in various states, including "flstik", "clurd" or "hmrwww".
This issue has been reproduced on two separate machines with the same controller.
Disabling MSI support by setting hw.arcmsr.msi.enable=0 in /boot/loader.conf is enough to make the problem go away.