Thread problem causing some calls to hang for 25

Thiago Macieira thiago at kde.org
Thu May 20 02:50:19 PDT 2010


Em Quinta-feira 20 Maio 2010, às 08:02:39, Carlsson, Johannes escreveu:
> Hi Guys
> 
> At Sony Ericsson this problem was quite frequent when turning on and off
> Bluetooth on our Android phone (Xperia X10i mini). Sometimes this
> operation took ~25s extra. We also managed to reproduce the problem on a
> Google G1, but this was a bit harder to do. I also reproduced it very
> frequently by adding a delay for every 3:rd (or something) call to
> _dbus_connection_acquire_io_path right after the connection lock had been
> released (I think this was the place at least).
> 
> When looking into the code for _dbus_connection_acquire_io_path I noticed
> that it releases the connection lock for a while. During this period
> another thread might already read the response and either put it in the
> incoming messages queue or already flagged it as completed (depending on
> which thread/call that did the actual reading). In Android there are
> several threads accessing the dbus-library at the same time, one which is
> dispathing events (android_server_BluetoothEventLoop.cpp) which calls
> dbus_watch_handle and a number of threads that will call
> dbus_connection_send_with_reply (android_bluetooth_common.cpp).
> 
> I tested this solution and it fixed this problem spot on (I tested by
> leaving the phone over night with a special sw that turned on and off
> Bluetooth constantly). During this test we also found a fd leak in the
> Android code, but that is another story :)
> 
> Is this patch something you could consider applying?

Yes, I think it should be applied. It did fix an issue for me.

I'm running KDE for a couple of days with all the fixes applied to see if I 
notice any regressions.
-- 
Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org
  Senior Product Manager - Nokia, Qt Development Frameworks
      PGP/GPG: 0x6EF45358; fingerprint:
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