Hi Ben, This seems to be where the polling rate is set: http://dxr.mozilla.org/mozilla-central/source/hal/gonk/GonkSensor.cpp#220
I think that this API is where it all starts: http://dxr.mozilla.org/mozilla-central/source/xpcom/system/nsIDeviceSensors.idl#28 addWindowListener http://dxr.mozilla.org/mozilla-central/source/dom/system/nsDeviceSensors.cpp#135 calls RegisterSensorObserver http://dxr.mozilla.org/mozilla-central/source/hal/Hal.cpp#545 which calls EnableSensorNotifications http://dxr.mozilla.org/mozilla-central/source/hal/gonk/GonkSensor.cpp#261 which calls SetSensorState http://dxr.mozilla.org/mozilla-central/source/hal/gonk/GonkSensor.cpp#246 which call SwtichSensor http://dxr.mozilla.org/mozilla-central/source/hal/gonk/GonkSensor.cpp#220 There is also this code path (actually, now that I found this path, I imagine its the path that is activating things): nsWindow constructor calls NotifyScreenInitialized: http://dxr.mozilla.org/mozilla-central/source/widget/gonk/nsWindow.cpp#154 nsAppShell::NotifyScreenInitialized creates an OrientationObserver: http://dxr.mozilla.org/mozilla-central/source/widget/gonk/nsAppShell.cpp#1023 OrientationObserer call EnableAutoOrientation http://dxr.mozilla.org/mozilla-central/source/widget/gonk/OrientationObserver.cpp#176 EnableAutoOrientation call RegisterSensorObserver http://dxr.mozilla.org/mozilla-central/source/widget/gonk/OrientationObserver.cpp#240 and follows the from RegisterSensorObserver above. Hopefully that helps. Dave Hylands ----- Original Message ----- > From: "Ben Kelly" <bke...@mozilla.com> > To: dev-b2g@lists.mozilla.org > Sent: Saturday, February 8, 2014 6:24:58 PM > Subject: [b2g] what triggers orientation sensor events? > > So while working on bug 965369 I instrumented the code in > hal/gonk/GonkSensor.cpp and observed that the poppit app receives > orientation sensor results every 50ms from the moment it is launched. These > results seem to ultimately be translated into 'devicemotion' events for the > app. > > In contrast, other apps do not trigger my GonkSensor.cpp instrumentation in a > repeated manner like this. > > Can anyone tell me what we look for to see how we enable the accelerometer > sensor for an app? > > I thought maybe registering for 'devicemotion' would do it, but poppit does > not do that immediately. It only does that the first time it needs > acceleration information, which is much later during a game. > > I also stripped the manifest down to just the name, icon, and invocation path > using app-manager. Still the poppit app spends a ton of time processing > these sensor results. > > Can anyone point me in the right direction? > > Thanks! > > Ben > _______________________________________________ > dev-b2g mailing list > dev-b2g@lists.mozilla.org > https://lists.mozilla.org/listinfo/dev-b2g > _______________________________________________ dev-b2g mailing list dev-b2g@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-b2g
