Stop mutex_lock() from eating pending events

When another task is holding the lock, mutex_lock() should call
task_wait_event_mask() to wait only for TASK_EVENT_MUTEX events.
If it calls task_wait_event(), any pending events are silently
discarded while its waiting for the the lock.

BUG=chromium:435611
BRANCH=ToT,samus
TEST=make buildall -j, and:

Before this change, I watched the EC console while shutting down
and rebooting Samus. I saw the request event arrive:

  [37.576295 LB lightbar_resume() requests 5 S3S0]
  [46.055725 LB_version]

But the lightbar task never saw it. Adding a bunch of debug
messages showed that it was being lost in mutex_lock().

After this change, the event is delivered:

  [30.167670 LB lightbar_resume() requests 5 S3S0]
  [30.171009 LB cur_seq 2 S3 returned pending msg 5 S3S0]
  [30.173816 LB running cur_seq 5 S3S0. prev_seq 2 S3]
  [32.410073 LB cur_seq 5 S3S0 returned value 0]
  [32.410865 LB running cur_seq 3 S0. prev_seq 2 S3]
  [39.938388 LB_version]

Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Change-Id: I011838538960cc57171f0a3c4cdee113d156e9ff
Reviewed-on: https://chromium-review.googlesource.com/231370
Reviewed-by: Randall Spangler <rspangler@chromium.org>

0 files changed, 0 insertions, 0 deletions