Crash when using Bluetooth

Thu Jan 3 13:59:22 UTC 2013

On Wed, Dec 26, 2012 at 7:33 PM, Dominique Rety <dominiquerety at hotmail.fr>wrote:

> **
>  Hi Kate,
>
> Thank you for your answer.
>
> I tried some traces and modifications into the lib QtConnectivity without
> success. It seems to me that functions into the library already contain
> calls to JNIThreadHelper class that should setup the Java environment by
> performing jvm->AttachCurrentThread(), but this doesn't solve the problem.
>
> At the same time, I performed some basic bluetooth tests directly through
> Java Eclipse (BluetoothAdapter.getDefaultAdapter.getName), which work fine
> on Nexus 7 with Android 4.2.
> However, our project contains some legacy parts that have already been
> developed in C, and using Qt would be the very best way to integrate them.
> Therefore I will only envision to implement a direct bridge between Java
> and C parts as a last resort if I can't find a viable solution with Qt.
>
> Consequently, I am very interested by your patches even before the next
> release, which could be helpful for us to take a decision for our
> development. Overriding and deploying the default Necessitas lib
> QtConnectivity is not a problem for me, at least for test purpose.
>

Now patches are on Review board https://git.reviewboard.kde.org/r/108113/ .
I would be happy if you could try them.

Sorry about delays publishing them

Kate

>
> Regards,
> Dominique
>
>
>
>
> ----- Original Message -----
> *From:* Kate Alhola <kate.alhola at gmail.com>
> *To:* Dominique Rety <dominiquerety at hotmail.fr>
> *Cc:* <necessitas-devel at kde.org> <necessitas-devel at kde.org%3E>
> *Sent:* Wednesday, December 26, 2012 4:36 PM
> *Subject:* Re: Crash when using Bluetooth
>
> On 13.12.2012, at 16.41, Dominique Rety <dominiquerety at hotmail.fr> wrote:
>
>   Hi,
>
> I am currently developing a telecommunication project involving Blutooth
> communication between Android devices. For this purpose, I'm trying to use
> Necessitas Bluetooth support and I experiment very similar problems that
> are described in the "Crash when using Bluetooth" (Kate Alhola) archive
> thread.
>
>
>
> There is several issues in current necessitas libQtConnectivity version. I
> have hopefully fixed most of them and i have version of libQtConnectivity
> that least works with my own applocation. I try to deliver patches to
> necessitas project so that fixes could be included in next release.
>
>   Environment:
> Java JDK 1.7.0_09
> Qt Creator 2.5.83 Based on Qt 4.8.3 running on Linux Suze
> Kit = Necessitas Qt 4.8.2 for Android armv7a
> Compiler = Android GCC (arm-4.4.3)
> Android target SDK = android-16
> Deploy to Nexus 7 with Android version 4.2.
>
> I firstly tried to deploy the btchat sample and I faced the same problem:
> JNI ERROR (app bug): accessed stale local reference 0xe680001d (index 7 in
> a table of size 4)
> VM aborting
> Fatal signal 11 (SIGSEGV) at 0xdeadd00d (code=1), thread 13965
> (.example.btchat)
>
> Setting traces in different source files of the connectivity library, I
> also noticed that the error happens when trying to use some member
> functions of QBluetoothLocalDevice (btchat sample requests for the local
> device name from the main function).
>
> I tried to bypass this problem by only creating the QBluetoothLocalDevice
> without requesting for the device name in the btchat application. The
> program then starts correctly.
>
> In the btchat application, the "Connect" button calls the
> QBluetoothServiceDiscoveryAgent::start function. This function randomly
> processes the request because it relies on discoveryState and deviceAddress
> members, which seem not to be initialized : either the discovery process
> freezes or the program aborts with an error (if luckily discoveryState and
> deviceAddress members get consistent values). I didn't try any further
> investigation. It seems to me that the connectivity library is compiled
> with qbluetoothlocaldevice_p.cpp, which just contains empty functions for
> the QBluetoothLocalDevice class, instead of a customized source for Android.
>
>
>
> Yes, that's case. The QBluetoothLocalDevice initializes static handles to
> java virtual machine that are then referenced by other modules. I have made
> fixes to several parts of libQtConnectivity
>
>
>   Is Bluetooth support for Android in Necessitas complete ?
>
>
> Most of, some functions are still missing but there are some bugs in
> current version
>
>   Is the btchat sample expected to work properly with Android ?
>
>
> I have not tried that one
>
>   Is there any specific configuration issue I could miss ?
>
>
> That's good question, what is origin of the bugs, does it work with older
> android
> Versions ? The source reason of bugs is JNI handles alocation that
> conflict with
> Current thread structure and some that handles are expired when used. I
> have only tested with
> Android 4.x
>
>   Is there any corrective or complement software I could download ?
>
>
> I could make my patches avaiable before next release  but overriding
> default necessitas libQtConnectivity requires some tricks
>
>   How can I progress on this issue ? What is the best way to get help and
> advices ?
>
>
> This list works fine.
>
> Kate
>
>
> Regards,
> Dominique RETY
> dominiquerety at hotmail.fr
>
>
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