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Date:      Fri, 6 Mar 2015 13:18:29 -0800
From:      Oleksandr Tymoshenko <gonzo@bluezbox.com>
To:        Milan Obuch <freebsd-arm@dino.sk>
Cc:        "freebsd-arm@freebsd.org List" <freebsd-arm@freebsd.org>
Subject:   Re: Raspberry Pi audio output
Message-ID:  <323C3582-8E9A-4112-8024-9D2B429EA55E@bluezbox.com>
In-Reply-To: <20150306094919.29056f20@zeta.dino.sk>
References:  <20150306094919.29056f20@zeta.dino.sk>

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> On Mar 6, 2015, at 12:49 AM, Milan Obuch <freebsd-arm@dino.sk> wrote:
>=20
> Hello,
>=20
> there is pcm0 device on Raspberry Pi, sysctl dev.pcm shows
>=20
> dev.pcm.%parent:=20
> dev.pcm.0.%desc: VCHQI audio
> dev.pcm.0.%driver: pcm
> dev.pcm.0.%location:=20
> dev.pcm.0.%pnpinfo:=20
> dev.pcm.0.%parent: vchiq0
> dev.pcm.0.play.vchans: 1
> dev.pcm.0.play.vchanmode: fixed
> dev.pcm.0.play.vchanrate: 48000
> dev.pcm.0.play.vchanformat: s16le:2.0
> dev.pcm.0.buffersize: 0
> dev.pcm.0.bitperfect: 0
> dev.pcm.0.dest: 0
>=20
> In /dev directory, there are just midistat and sndstat devices,
> cat /dev/sndstat shows
>=20
> Installed devices:
> pcm0: <VCHQI audio> (play) default
>=20
> How can I use this device? I would like to check it and possibly =
use...
> Also, is it connected to 3.5 mm jack or do we have sound through HDMI?

It=E2=80=99s standard OSS interface, you can either access /dev/dsp0 =
directly or use
one of audio library (e.g. libao). To test it just install mpg321 and =
try to=20
play some mp3s.

Audio output is connected to both HDMI and 3.5mm jack and controlled
by  dev.pcm.0.dest sysctl. Available values are:

0 - auto. VideoCore decides where to direct audio output based on
    current HDMI mode.
1 - headphones, audio goes to 3.5mm jack
2 - HDMI. Audio goes to HDMI display. Please note that not every HDMI
    mode supports audio.=20=



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