RX100 Control Ring Not Working?

walker29 wrote:

Focus Mode > DMF and/or MF Assist > On can have an effect on the control ring not doing what you set it to do under Control Ring.

This fixed the problem for me. While messing around with the Fn button settings, I set Focus Mode to DMF, and this disabled the A/S/P Mode Control Ring Functions. Choosing another Focus Mode re-enabled the functions. Much better than a system reset!