I'm running openelec+xbmc connected to my TV via HDMI cable, and my TV remote has stopped being able to control XBMC.

I'm not sure if it is the settings in xbmc/openelec that are incorrect, if there is something funny with the TV, or if it is the cable or the rpi itself.

I've power-cycled the TV and the rpi separately and together, and I can see that the remote is working OK because it controls the TV as usual. My TV is a panasonic TH-P42S10Z.

I have a possibly related issue of sound no longer working, when it previously did.

Does anyone have any ideas on how to tackle this?