I have a Lenovo Thinkpad Yoga S3 (spring 2015). it has a rather strange bug when it comes to the internal keyboard:
When waking up from suspen, the internal keyboard no longer reacts -- some times.
One can reboot, and the keyboard will work in the BIOS, but not at the cryptsetup login screen. After logging in to the system with a USB keyboard and booting linux entirely, the keyboard will mostly works again. The problem is present in kernel 4.0, but only happens once every few months. On kernel 4.2.5, it happens almost every time the computer suspends.
None of the output as lspci ur lsusb gives any information related to a keyboard nor is there any significant different between times when the keyboard is working and isn't working. None of the treatments for similar keyboard bugs on forums does anything and dmesg gives no helpful error message.
So I wonder: How can I go about trying to debug this? How can I find out what driver is used for the keyboard, and how can I debug it?