[vlc-devel] Question about vlc_mutex_lock/unlock in Android

[Nick Briggs]

I'm seeing behavior from vlc_mutex_lock/vlc_mutex_unlock in VLC (git master branch at commit 60b01d4cbea10327517429c42bcf31cccfbd2567) on Android (4.0.3, kernel 3.0.15-I9100UHLPE-CL200654, a Samsung Galaxy S II) that I don't expect, and wonder if anyone else has encountered the same issue --

I have an input processing thread (Thread 2, below) that is synchronizing with a network event thread (Thread 1), and pretty repeatably I'll see
...
Thread 1: 	mutex lock
Thread 2:	mutex lock (blocks, expected)
Thread 1:	mutex unlock
Thread 2:	mutex lock taken (as expected)
Thread 2:	mutex unlock
Thread 1:	mutex lock
Thread 2:	mutex lock (blocks, expected)
Thread 1:	mutex unlock	(at this point thread 2 should have got control since it was waiting on the mutex that was just released...)
Thread 1:	mutex lock		(...however it does not, but Thread 1 continues to handle events...)
Thread 1:	mutex unlock
Thread 1:	mutex lock
Thread 1:	mutex unlock
Thread 1:	mutex lock
Thread 1:	mutex unlock
Thread 1:	mutex lock
Thread 1:	mutex unlock

... this repeats until the video output freezes because Thread 2 never again makes any progress.

-- Nick Briggs
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