summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorPeng Xu <pengxu@google.com>2015-10-26 15:14:43 -0700
committerPeng Xu <pengxu@google.com>2015-10-27 21:46:40 +0000
commit20483c49377fdb0330d9dfbbb2168b470c0b29d3 (patch)
treebfcfdcf6a52bf58c39664e0dc14a539b86c68e2e
parent2ac7405bda4f621f07cbcc0b562d16f7a9611c7b (diff)
downloadframeworks_native-20483c49377fdb0330d9dfbbb2168b470c0b29d3.zip
frameworks_native-20483c49377fdb0330d9dfbbb2168b470c0b29d3.tar.gz
frameworks_native-20483c49377fdb0330d9dfbbb2168b470c0b29d3.tar.bz2
Avoiding flush on-change sensors at subscription
Initial sensor flush at subscription is a mechanism to avoid sensors to get stale samples before subscription happens. However, there is a slight chance that a most recent sample will be lost during the flush process. This is OK for continuous sensors but problematic in on-change sensor as on-change event does not come continuously and a lost event can cause inconsistent state in client. Flush at subscription of on-change sensor is disabled in this CL to avoid new important on-change event to be discarded during the initial flush process. Bugs: b/24647069 b/25241873 b/24804819 Change-Id: Ibda099c6b9f5fb6e200f13cf13a850b0026e9e7c
-rw-r--r--services/sensorservice/SensorService.cpp13
1 files changed, 9 insertions, 4 deletions
diff --git a/services/sensorservice/SensorService.cpp b/services/sensorservice/SensorService.cpp
index 40b21a9..fd72b23 100644
--- a/services/sensorservice/SensorService.cpp
+++ b/services/sensorservice/SensorService.cpp
@@ -912,10 +912,15 @@ status_t SensorService::enable(const sp<SensorEventConnection>& connection,
status_t err = sensor->batch(connection.get(), handle, 0, samplingPeriodNs,
maxBatchReportLatencyNs);
- // Call flush() before calling activate() on the sensor. Wait for a first flush complete
- // event before sending events on this connection. Ignore one-shot sensors which don't
- // support flush(). Also if this sensor isn't already active, don't call flush().
- if (err == NO_ERROR && sensor->getSensor().getReportingMode() != AREPORTING_MODE_ONE_SHOT &&
+ // Call flush() before calling activate() on the sensor. Wait for a first
+ // flush complete event before sending events on this connection. Ignore
+ // one-shot sensors which don't support flush(). Ignore on-change sensors
+ // to maintain the on-change logic (any on-change events except the initial
+ // one should be trigger by a change in value). Also if this sensor isn't
+ // already active, don't call flush().
+ if (err == NO_ERROR &&
+ sensor->getSensor().getReportingMode() != AREPORTING_MODE_ONE_SHOT &&
+ sensor->getSensor().getReportingMode() != AREPORTING_MODE_ON_CHANGE &&
rec->getNumConnections() > 1) {
connection->setFirstFlushPending(handle, true);
status_t err_flush = sensor->flush(connection.get(), handle);