K 10
svn:author
V 5
gonzo
K 8
svn:date
V 27
2016-12-27T19:08:08.503425Z
K 7
svn:log
V 752
[rpi] Fix bcm2835_audio locking and samples starvation

Rework general approach to locking and working with audio worker thread:

- Use flags to signal requested worker action
- Fix submitted buffer calculations to avoid samples starvation
- Protect buffer pointers with locks to fix race condition between callback
  and audio worker thread
- Remove unnecessary vchi_service_use
- Do not use lock to serialize VCHI requests since only one thread issues them now
- Fix unloading signaling per hselasky@ suggestion
- Add output to detect inconsistent callback data caused by possible firmware bug
  https://github.com/raspberrypi/firmware/issues/696
- Add stats/debug sysctls to troubleshoot possible bugs

PR:		213687, 205979, 215194
MFC after:	1 week

END