The function rrGetPixmapSharingSyncProp() will check for the PRIME sync property "PRIME Synchronization" on each output and return false if any of the output has this property set to false.
To do so, it will call RRGetOutputProperty() twice for each output, once with pending true and once with pending false to cover both possibilities.
However, reading the implementation of
RRGetOutputProperty(), it appears
that if the property is not pending, the code will return the current
value even if invoked with pending true.
So the second call to RRGetOutputProperty() with pending false seems superfluous.