commit e7bd2580e55c618e98fd95619f2e4e44a9d6a332
author Nick Vaccaro <nvaccaro@google.com> Fri Oct 17 20:32:10 2014 -0700
committer Nick Vaccaro <nvaccaro@google.com> Fri Oct 17 20:45:46 2014 -0700
tree e1d68c6d3830129332b41c455a2e0d91b58a7cdd
parent 199449a4c52ff30e2804ab0bccf99b466c594c7c

sensors: mpu6515: grab wakelock on significant motion event

The kernel sensor driver grabs a half second wakelock to allow time
for this HAL to read the significant motion event from the kernel and
grab its own wakelock.  The HAL holds the wakelock until Sensor
Services calls poll() again, assuring that Sensor Services has
read the SMD event and will have grabbed its own wakelock.

Bug: 16540661
Change-Id: I1c88cd9386a9f711e6cba81a14539b835f4e7414

6515/libsensors_iio/Android.mk

diff --git a/6515/libsensors_iio/Android.mk b/6515/libsensors_iio/Android.mk
index 94e03f1..7ae62cd 100755
--- a/6515/libsensors_iio/Android.mk
+++ b/6515/libsensors_iio/Android.mk
@@ -153,6 +153,7 @@
 LOCAL_SHARED_LIBRARIES += libdl
 LOCAL_SHARED_LIBRARIES += liblog
 LOCAL_SHARED_LIBRARIES += libmllite
+LOCAL_SHARED_LIBRARIES += libhardware_legacy
 include $(BUILD_SHARED_LIBRARY)
 
 include $(CLEAR_VARS)

6515/libsensors_iio/sensors_mpl.cpp

diff --git a/6515/libsensors_iio/sensors_mpl.cpp b/6515/libsensors_iio/sensors_mpl.cpp
index 2df1a8b..c2a36f4 100755
--- a/6515/libsensors_iio/sensors_mpl.cpp
+++ b/6515/libsensors_iio/sensors_mpl.cpp
@@ -16,6 +16,7 @@
 
 #define FUNC_LOG LOGV("%s", __PRETTY_FUNCTION__)
 
+#include <hardware_legacy/power.h>
 #include <hardware/sensors.h>
 #include <fcntl.h>
 #include <errno.h>
@@ -61,6 +62,9 @@
 struct simplehead *headp;
 static pthread_mutex_t flush_handles_mutex = PTHREAD_MUTEX_INITIALIZER;
 
+static const char *smdWakelockStr = "significant motion";
+static pthread_mutex_t mSMDWakelockMutex = PTHREAD_MUTEX_INITIALIZER;
+
 static struct sensor_t sSensorList[LOCAL_SENSORS];
 static int sensors = (sizeof(sSensorList) / sizeof(sensor_t));
 
@@ -121,6 +125,10 @@
     struct pollfd mPollFds[numFds];
     SensorBase *mSensor;
     CompassSensor *mCompassSensor;
+
+    /* Significant Motion wakelock support */
+    unsigned long mSMDEventsPending;
+
 };
 
 /******************************************************************************/
@@ -132,6 +140,9 @@
     mCompassSensor = new CompassSensor();
     MPLSensor *mplSensor = new MPLSensor(mCompassSensor);
 
+    /* No significant motion events pending yet */
+    mSMDEventsPending = 0;
+
    /* For Vendor-defined Accel Calibration File Load
     * Use the Following Constructor and Pass Your Load Cal File Function
     * 
@@ -197,6 +208,16 @@
     int nbEvents = 0;
     int nb, polltime = -1;
 
+
+    pthread_mutex_lock(&mSMDWakelockMutex);
+    if (mSMDEventsPending) {
+        mSMDEventsPending--;
+        /* If there are no more events pending, release our wakelock */
+        if (!mSMDEventsPending)
+            release_wake_lock(smdWakelockStr);
+    }
+    pthread_mutex_unlock(&mSMDWakelockMutex);
+
     struct handle_entry *handle_element;
     pthread_mutex_lock(&flush_handles_mutex);
     if (!SIMPLEQ_EMPTY(&pending_flush_items_head)) {
@@ -243,9 +264,21 @@
                     nb = ((MPLSensor*) mSensor)->
                                     readDmpSignificantMotionEvents(data, count);
                     mPollFds[i].revents = 0;
-                    count -= nb;
-                    nbEvents += nb;
-                    data += nb; 
+                    if (nb) {
+                        pthread_mutex_lock(&mSMDWakelockMutex);
+                        /* if mSMDEventsPending != 0, the wakelock is already held */
+                        if (!mSMDEventsPending) {
+                            /* Hold wakelock until Sensor Services reads event */
+                            acquire_wake_lock(PARTIAL_WAKE_LOCK, smdWakelockStr);
+                            LOGI_IF(1, "HAL: grabbed %s wakelock", smdWakelockStr);
+                        }
+                        mSMDEventsPending++;
+                        pthread_mutex_unlock(&mSMDWakelockMutex);
+
+                        count -= nb;
+                        nbEvents += nb;
+                        data += nb;
+                    }
                 } else if (i == dmpPed) {
                     nb = ((MPLSensor*) mSensor)->readDmpPedometerEvents(
                             data, count, ID_P, 0);