[alsa-devel] Fwd: ALSA queries

[Takashi Iwai]

On Tue, 07 Aug 2018 15:12:08 +0200,
Chakravarthi Pradeep wrote:
> 
> Dear Takashi,
> 
> Thanks for your reply.
> 
> > The "period" in ALSA PCM definition represents the interval time (or
> > frames) of the periodical interrupts on the ring buffer.  If the irq
> > is issued for each 256 frames while the ring buffer size is 1024
> > frames, periods = 1024/256 = 4.  The periods_min defines the minimal
> > number of periods the hardware may accept.
> 
> Is it  256 frames or  256 bytes ?

In the case above it's in frames.  But it can be defined in bytes
depending on the hardware spec.  Some hardware defines in the time
unit (like msec), too.

> fuser -v /dev/snd/* output is
>                                          USER
>   PID   ACCESS    COMMAND
> /dev/snd/controlC0         Dell                                   1815
> F.....           pulseaudio

Now you know it.  And remember that PA is often die-hard.


Takashi