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  1. #1
    Registered User
    Join Date
    Dec 2009
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    3

    Graphics freeze on dualcore devices

    Hi all,

    I'm developing an application which makes intensive use of JSR82 bluetooth as well as graphics. Everything works fine on single core devices.

    But on dual core devices (like N95 and some communicators) I figured out that if the bluetooth connection closes and concurrently a graphics operation happens (repaint on canvas), the graphics thread freezes. It seems like that there's a deadlock somewhere within the VM. I tried to work around this problem, but it only happens when the BT connection itself closes (or gets closed by the other side), not when I close the connection via API. This makes it impossible to get around that. I tried the newest firmware updates, but that makes no difference.

    Is there any chance that Nokia will fix this issue?

    Kind regards

    Max

  2. #2
    Registered User
    Join Date
    Dec 2009
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    3

    Re: Graphics freeze on dualcore devices

    Good to see that neither Nokia nor somebody else cares about such severe problems. Now that sensible other smartphone like Android exist, Nokia and Symbian can rest in peace.

  3. #3
    Super Contributor
    Join Date
    Apr 2007
    Posts
    2,708

    Re: Graphics freeze on dualcore devices

    Well it's not like we don't care, it'r more like it might also be a problem of just your software : i.e some multi-threading problem... Multi-threading is a complex thing on its own, personally I have used BT and Canvas in the same app without any problem and the device I was developing on was a N95 which is a dual-core device... The same software worked as well on a 6233 (S40) and on a N96 (single-core)...

  4. #4
    Registered User
    Join Date
    Dec 2009
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    3

    Re: Graphics freeze on dualcore devices

    Hi Tiger,

    thanks for your reply!

    Well, the application runs pretty well on a large amount of devices of several OEMs (Nokia, SonyEricsson, Samsung, with PhoneME on Windows Mobile and with special libraries on BlackBerry) without this problem. And it really just occurs on dualcore devices!

    I know that multithreading can get pretty tricky, so I tried to simplify my program and to get rid of some unneccessary repaints. The less I repaint, the less often does it freeze. The other way round, I did massive repaints (just canvas.repaints) and it froze regularly on exactly the moment, when the Bluetooth connection aborted (the bt sign disappeared).

    Sure, I could be wrong, but I was stepping through all the code, debugged it for several days and my conclusion is, that there is some kind of bug in the firmware. The other usages of BT in my app is no problem (app blocks GUI, opens connection, does something, disconnects and releases GUI). It first appeared when I left the connection open and the devices were moved away from each other until the connection closed. It's really a nasty problem (although it does not appear that often than earlier), so if anyone got a hint for me, it'd be really cool!

    Regards

    Max

  5. #5
    Super Contributor
    Join Date
    Apr 2007
    Posts
    2,708

    Re: Graphics freeze on dualcore devices

    hhmmm... ok sounds like it might be a device specific problem..
    Have you tried it on another N95 as well ?
    I can't remember the funtionality of JSR-82 specifically but is there some method to see when a connection is lost ? And if so (maybe a listener interface?) could that be used to force the connection to close in a good manner ?
    I am just thinking up load now, actually I haven't experienced such a problem and I only scratched the surface of JSR-82 like 2 years ago so it's not that fresh in my head

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