Yoga 370 Keyboard won't respond

[robla64]

I have a Yoga 370 running Fedora for the last 2 years. Recently the keyboard will not respond to any input (even the CAPS LOCK light won't come on.)
The touchscreen keyboard shows up in this situation.
If I plug in a USB keyboard, then the normal keyboard will start working again.
Is there a sensor that thinks its in touchscreen mode?

[Gulash]

The same happened for me recently in a different model.
Turned out I didn't insert the keyboard ribbon properly when I disassembled it 2 years earlier.
It took 2 years for the ribbon to slid out enough of the socket for the keyboard to stop working, can you imagine ? At first two keys stopped responding to a press, then gradually the whole keyboard stopped working within 15 minutes or so.

Of course after reinserting the ribbon the keyboard works properly again. Try to reconnect the ribbon in the socket and see if it helps.