This issue can be reproduced with 4.15 Bionic as well.
However, I can't see any CPU in offline state for a 4.15 Bionic P8 node
after boot.
** Package changed: linux-signed-hwe-edge (Ubuntu) => linux (Ubuntu)
** Summary changed:
- Unable to put offline CPU back online on B-hwe-edge P9
+ Unable
** Description changed:
- ubuntu@baltar:~$ cat /sys/devices/system/cpu/offline
+ You will see these CPUs in offline state after boot.
+
+ ubuntu@baltar:~$ cat /sys/devices/system/cpu/offline
156-159
- ubuntu@baltar:~$ echo 1 | sudo tee /sys/devices/system/cpu/cpu156/online
+
