It does, but it's not in there for 6.8.x yet.....No it's not working. Does your tree have commits in https://github.com/raspberrypi/linux/pull/6046 applied?
Or just run rpi-update, like the post tells you to do.
I'm just building 6.6.22 to see if it works.
I can't run rpi-update on Ubuntu, wish I could.

EDIT(1)
It worked:
Code:
[ 1.016123] mmc0: Command Queue Engine enabled

EDIT(2)
Kernel:
Code:
Linux raspberrypi 6.6.22 #1 SMP PREEMPT Sat Mar 23 18:33:21 GMT 2024 aarch64 aarch64 aarch64 GNU/Linux
Statistics: Posted by SW1TCH0NY0U — Sat Mar 23, 2024 6:28 pm