how do we show bs-tooltip on disabled button?

here is my code
i am checking condition on bs-tooltip and ng-style that if button is disabled on hover tooltip will show but it not works

<button class="btn btn-primary"   bs-tooltip="ctrl.anyMachinesError || ctrl.anyMachinesDirty || ctrl.machinesSubmitted ? 'Please Configure and Save all Machines':' '" data-placement="right"  ng-click="ctrl.onSubmit()"  ng-disabled="ctrl.anyMachinesError || ctrl.anyMachinesDirty || ctrl.machinesSubmitted"
     ng-style="{'pointer-events':ctrl.anyMachinesError || ctrl.anyMachinesDirty || ctrl.machinesSubmitted ? 'none' : ''}">
       Submit & Next