Hi Everyone,

These 2 patches deal with issues that may arise if the polling delay value used
for passive polling is at odds with the polling delay values used otherwise.

The first patch simply eliminates the need to worry about possible negative
polling delay values by changing the data type used for representing them
to unsigend int.

The other patch adds a sanity check to ensure that "passive" polling will not
be less frequent than "regular" polling.

Thanks!