Similar or same problem here (ThinkPad X61 tablet)
I use the tablet as multi-user.
On "first" user [ctrl+alt+f7] the pen does not work On "second" user [ctrl+alt+f8] the pen works.
So, it's not a hardware issue.
I don't know if it helps: /var/log/Xorg.2.log:[ 15853.585] (EE) PreInit returned 8 for "Serial Wacom Tablet stylus"
Similar or same problem here (ThinkPad X61 tablet)
I use the tablet as multi-user.
On "first" user [ctrl+alt+f7] the pen does not work
On "second" user [ctrl+alt+f8] the pen works.
So, it's not a hardware issue.
I don't know if it helps: Xorg.2. log:[ 15853.585] (EE) PreInit returned 8 for "Serial Wacom Tablet stylus"
/var/log/