The Cix P1 81x0 SoCs firmware releases by different manufacturers have a bug in the SMMU v3 Event Queue, causing an interrupt storm that manifests as various problems. These range from missing features to crashing applications/desktops and kernel panics. Eric Dedeoglu on GitHub conducted an in-depth analysis of this bug and found a fix for it. If you want to learn more about it, we highly recommend reading his article.
While Eric provides an install script on his GitHub, it only applies to Debian-based systems. Since Bred is based on ArchLinuxARM, we packaged the needed files for your convenience.
smmu-evtq-fixsudo pacman -Syu smmu-evtq-fix
That's it. No reboot required (unless you have already limited your PCIe speed to Gen. 3 in the firmware. In that case, you will need to reboot your machine and revert this setting).
Without Eric's analysis, this bug would not have been fixed. Thank you so much for your excellent work!