The PLL lock and recalibration signals can be monitored to detect the loss of lock or the requirement to recalibrate (caused by a large temperature change since the last lock request):
The PLL_STATUS[1] PLL_LOCK status bit gives the VIDEOx PLL lock state.
The PLL_STATUS[2] PLL_RECAL status bit informs whether the PLL must be uncalibrated.