I hesitatingly upgraded to 18.04, and the 4.15 kernel that it comes with booted just fine, so it seems like this issue is limited to the 4.13 kernels that come with 17.10/16.04 HWE.
This is what I have now:
$ lsb_release -rd Description: Ubuntu 18.04 LTS Release: 18.04
$ uname -a Linux thinkpad 4.15.0-24-generic #26-Ubuntu SMP Wed Jun 13 08:44:47 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
I hesitatingly upgraded to 18.04, and the 4.15 kernel that it comes with booted just fine, so it seems like this issue is limited to the 4.13 kernels that come with 17.10/16.04 HWE.
This is what I have now:
$ lsb_release -rd
Description: Ubuntu 18.04 LTS
Release: 18.04
$ uname -a
Linux thinkpad 4.15.0-24-generic #26-Ubuntu SMP Wed Jun 13 08:44:47 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux