CODEWITHSUNDEEP
androidbluetooth-lowenergybufferedwriter
tosa
tosa

Reputation: 421

BuffedWriter save of large amounts of BLE data causes GKI error

I have an Android app from which I receive BLE data (every 62ms via notifications). The app can save data via a BufferedWriter to a file. Upon ending the save of large amounts of data, I see an error such as this: GKI_exception out of buffers https://code.google.com/p/android/issues/detail?id=65455 (except my code is not scanning but receiving notifications). I don't see this error for 100s of kB saves, but I see it on 1-2MB saves in logcat, and on >5-6MB saves I need to power cycle the Nexus 7 (the app and BLE become totally unresponsive). I call close() on the BufferedWriter at the end of the save. How do I fix this?

Upvotes: 0

Views: 190

Answers (1)

devunwired
devunwired

Reputation: 63293

The issue is likely thread related. You need to make sure that the "save" operation (which is writing file data to disk...an operation that takes a long time) is not happening in the same thread context that could block your BLE notifications or a related callback. If you block a thread that keeps a BLE callback method from returning, you will see the Bluetooth stack get starved, which is what that callback usually means.

Simplest thing is to always make sure you write file data in a new background thread (like an AsyncTask, Thread, or IntentService for instance), ensuring that regardless of what thread you were coming from, the long write to flash memory won't block the current context.

Upvotes: 1

Related Questions