Solution when you can only use the left side of Wacom's pen tab on Ubuntu

This is due to Android mode. You can switch to PC mode by pressing two buttons on the outside of the tablet at the same time for about 10 seconds.

reference

• https://github.com/linuxwacom/xf86-input-wacom/wiki/Known-Issues#issue-my-wacom-intuos-ctl-4100-or-ctl-6100-seems-to-be-miscalibrated-has-a-dim-status-led
• https://www.wacom.com/ja-jp/support?guideTitle=%E3%80%90%E3%82%88%E3%81%8F%E3%81%82%E3%82%8B%E8%B3%AA%E5%95%8F%E3%80%91Wacom-Intuos%E3%82%92Android%E7%AB%AF%E6%9C%AB%E3%81%A7%E4%BD%BF%E7%94%A8%E4%BA%88%E5%AE%9A%E3%81%AE%E3%81%8A%E5%AE%A2%E6%A7%98%E3%81%B8&guideId=016-502