[LAU] Is ALSA using hrtimer?

[Niels Mayer]

>> "ALSA uses the hrtimer as a precise timing source. The ALSA sequencer
>> code also can use this timing source."

BTW, now that I've enabled hr timer, I notice that qtractor 's
View->Options->MIDI->Playback has an entry for
"Queue timer (resolution):
 [ (default), system timer (1000 Hz), HR timer (1000000000 hz), PCM
Playback 0-0-0. (slave), PCM Playback 0-0-1 (slave), ... ]"

What happens if I use "HR timer" instead of  "(default)" or a specific
PCM slave, when recording/playing back audio clips ?
Does "PCM playback (slave)" mean the audio sample-clock is sync'd to
the midi clock, or vice-versa? And if snd-hrtimer is available,
wouldn't both audio and midi be using the same clock? (per Grant's
comment ''CONFIG_SND_HRTIMER says: "ALSA uses the hrtimer as a precise
timing source. The ALSA sequencer code also can use this timing
source."'' )

W/r/t qtractor, does (default) "do the right thing" or should I be
choosing a specific option based on use?

I guess I'll find out...

Niels
http://nielsmayer.com