alt Hacker Newsone of the biggest issue i see is the devicetree nonsense. It makes every single laptop and bios version very unique and requires a lot of housekeeping. There are also big chunks of work (as i understand it) to be done around hibernate and decent suspend support.
My experience (wanted to use x13s as daily sriver) is that there was good progress for about a year, until jhovold was leading the charge, but something expired and qualcom as far as i can tell forgot that some progress should happen on x1 and x8c as well as x2.
It feels deeply unfortunate that even with Windows on AArch64 requiring ACPI that it still doesn’t suffice for Linux, unlike on x86.
And I know a lot of that lies on the vendors, but it does feel unfortunate (from a standardisation/conformance/certification point of view) that Windows requiring it doesn’t make it easy to boot other OSes!