So I've tested several firmware version to track down where the issue was introduced and the firmware that I was able to get this working correctly is P16. (LSI HBAs LSI SAS2308/SAS2008)   To those who are seeing this error, you might want to downgrade to P16 firmware and your FSTRIM would work with your SSDs (obviously if it is supported).   Tested firmware version:   P14 -> YES P15 -> YES P16 -> YES P17 -> NO P18 -> NO P19 -
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