strange keyboard problem with synaptics controller

[Daniel Drake]

I've seen this issue on several XO-1s with the Synaptics hardware, and
now on an XO-1.5 ramp unit running firmware Q3A36.

Upon booting, the keyboard under Linux doesn't work right, e.g.
pressing q results in d (fictional example -- can't recall if this is
an exact example of a mismatch).

Rebooting into OFW tests confirms the mismatch between keys, and also
shows that after releasing the key, the mismatched key is displayed as
being held down.

The problem continues after powering off and on again. The solution is
to disconnect the charger and the battery, then reconnect, causing an
EC reset.

What would be the next steps for debugging the next time we see this?

Daniel