tree 2ccc99ad3a43207b6b533b5e35c021994e794bc9
parent 94c27a389be20787a4439ee94e3b907ac16b22bb
author Ramkumar Radhakrishnan <ramkumar@codeaurora.org> 1421803078 -0800
committer Ramkumar Radhakrishnan <ramkumar@codeaurora.org> 1422929258 -0800

sde: Implement sequence locker to lock across multiple APIs.

1. Lock prepare() and set() APIs using sequence entry and sequence
   exit lock respectively to prevent the critical section being
   accessed by other threads.
2. Wait for sequence wait lock on HotPlugEvent thread or any other
   binder threads(Eg. dumpsys), before it accesses the critical region.
3. Prevent deadlock during multiple prepare() calls before a set().

Change-Id: I5443675c870ed2967615ec383dd2d59ded30b52b