>The Linux kernel has supported UAS since 8 June 2014 when the version 3.15 was released.However, some distributions of Linux such as Ubuntu (from v11.xx onwards) have suffered from issues with the implementation of the UAS protocol.

I assumed UASP is standard now, Every USB 3.0 or > storage devices, enclosures I've bought over past 5 years have supported it but it seems some Linux distros are still having trouble.

Searching for uas under ArchLinux ARM on Raspberry Pi 3 which is booted using a SSD drive with UASP enclosure returned nothing.