Hardware Volume Control + RPi2 + IQaudIO DAC+

gearhead

Frank,

I played a bit with it last night. One thing I notice is that your version of alsamixer is newer than mine. Mine reports v1.0.28 and yours appears to be v1.0.29 Don't know of that has anything to do with it.

If I select Hardware Volume from the mpd settings page, I can no longer adjust volume from the UI, it just pops back to 0, but I can adjust the volume from alsamixer 'PCM' level adjustment. It behaves like the others have said about hardware volume where it has very little output below 50%, and gets quite loud and clips above 95%.

Keith

hondagx35

Hi Keith,

you are using this image (RuneAudio_rpi2_0.3-beta_20150304_2GB.img)?

but I can adjust the volume from alsamixer 'PCM' level adjustment.

Then try "PCM" instead of "Digital".

Frank

gearhead

kwanying wroteI got it working by changing the snd_rpi_iqaudio_dacplus to IQaudIODAC (since "aplay -l" show IQaudIODAC as the hardware ID *on PI2 Image*)

redis-cli hset acards_details IQaudIODAC "{\"sysname\":\"IQaudIODAC\",\"extlabel\":\"IQaudIO Pi-DAC+ (I&#178;S)\",\"mixer_numid\":\"1\",\"mixer_control\":\"PCM\",\"hwplatformid\":\"01\",\"type\":\"i2s\"}"

I was able to get it to use hardware volume control with this command, followed by the

/srv/http/command/refresh_ao

I also get this, but it works.

# /srv/http/command/refresh_ao

Notice: Undefined offset: 0 in /srv/http/app/libs/runeaudio.php on line 2316

Notice: Undefined offset: 0 in /srv/http/app/libs/runeaudio.php on line 2317

Warning: socket_write(): unable to write to socket [32]: Broken pipe in /srv/http/app/libs/runeaudio.php on line 99

As for the version of RuneAudio I'm running, the date on my image matches the one on the downloads page for the Pi2.

gearhead

I learned a couple things which drive some of the confusion and still have a couple questions.

The HiFiBerry and IQaudIO use the same DAC (PCM5122). The IQaudIO uses a GPIO pin to mute the card (it's use is optional and it appears the card will work fine without using it.
The driver difference between them and the reason that you need to load one or the other overlay in /boot/config.txt to get functionality is due to the difference in which i2c address the chip is set to. IQaudIO uses 0x4c and HiFIBerry uses 0x4d. Other than this, there are no differences on the driver side for either card. The details are here in the *.dts files
I cannot comment on any audio differences between them. It appears that IQAudio has other functionality/features which can be found on their web page.
The reason that the IQaudIO dac+ driver does not work with Frank's redis script is that the IQaudIO_DAC+ and IQaudIO_DAC dts files are identical and pass the same 'sysname' of the device to the OS as iqaudio-dac (The OS has no idea what iqaudio-dac+ is).
I am curious about the difference between my image alsa-utils version number to Frank's. I was able to get the same version by "pacman -S alsa-utils" but I do not know if this is intended or not.
From a read of the IQaudIO installation instructions, http://www.iqaudio.com/downloads/IQaudIO.pdf the newer (late Jan 2015) releases change the channel for hardware volume. Earlier kernels use playback digital and the later ones use PCM and Playback and Playback Boost. My kernel is 3.18.7-3 and is, according to Gordon's pdf, a later kernel...

Does this all make sense?

I am running a homebrew PCM5122 based card and am at 0x4c which is why iqaudio-dac overlay works with my card. I assume I am running a later kernel to Frank which is why my hardware volume shows up in Alsamixer on 'PCM' instead of 'playback digital'.

Gearhead

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