The IOMMU issue. Boot and USB problems.

[27leguas]

IOMMU in one very important source of boot and USB problems in Linux.
I have created a detailed documentation on this topics:

• What IOMMU controller does?
• Different fixes for boot and USB problems related to IOMMU in Linux
• How to tell if you are running on an emulated IOMMU or a Hardware one?
• How to check if hardware IOMMU controller and passthrough are enabled?

I have posted the documentation in the Ryzen 5 4500U section:
https://bbs.minisforum.com/threads/the-iommu-issue-boot-and-usb-problems.2180/