angularjs - Angular: Using ng-disabled if forms in partials in child controllers have ng-invalid attribute -

i've been struggling few hours, , i'm coming blank. wouldn't build this way, else's code , refactoring way beyond scope of part of project. need works within way it's built. here rough approximation of html looks like:

<div ng-controller=outercontroller outercontroller>     <button ng-click="save()" ng-disabled="?????">save</button>     <div ng-controller="partialcontroller partialcontroller>         <div partial can replicated bunch of times , called recursively>             <form name="partialform></form         </div>     </div> </div> 

so, there can ton of instances of partialform within dom, may different degrees of childhood outercontroller, , want able check if of them have ng-invalid ng-disabled on save button.

any thoughts? :)