Since I still use PS2 KVM, I've tried a number of PS2--USB adapters. The Startech USBPS2PC is the most reliable I've seen. It works with most Win and Linux systems, even when operating at the BIOS level.
The second product from StarTech to fail... out of 2!
Response from startech.comBy Malcolm, Customer Support, July 3, 2018
We apologize this adapter has failed, and would like to help. It's covered by a 2 year warranty and lifetime technical support. Please reach out to our Support team so we can troubleshoot and get it replaced as appropriate.