[alsa-devel] Duplicate wake-ups in pcm_lib.c

[pl bossart]

> I couldn't figure out who generates this null event, and even better
> it does not show in the report printed by my test app. I am somewhat
> lost here as to how snd_pcm_playback_poll works.

Not sure if this is related to my previous post, but PulseAudio seems
to only sleep every other time poll is called. Somehow there's still a
spurious wakeup.

E: rtpoll.c: rtpoll_run
E: rtpoll.c: poll timeout: 188 ms
E: rtpoll.c: Process time 0 ms; sleep time 188 ms
E: rtpoll.c: rtpoll_run
E: rtpoll.c: poll timeout: 189 ms
E: rtpoll.c: Process time 0 ms; sleep time 0 ms
E: rtpoll.c: rtpoll_run
E: rtpoll.c: rtpoll finish
E: rtpoll.c: rtpoll_run
E: rtpoll.c: poll timeout: 188 ms
E: rtpoll.c: Process time 0 ms; sleep time 189 ms
E: rtpoll.c: rtpoll_run
E: rtpoll.c: poll timeout: 189 ms
E: rtpoll.c: Process time 0 ms; sleep time 0 ms