[pulseaudio-discuss] Driver falls back to software volume

[peterten01 at yahoo.com]

Hi,

I'd like to provide an ALSA driver which is designed to support pulseaudio by default (if that is possible).
The driver works fine with aplay and alsamixer. It provides 6 channels and volume controls.
- One 'Master Playback Volume' (Mono)
- One 'PCM Playback Volume' (6 channels)

However, when I want to add an alsa-sink in pulseaudio the hw volume is not used.

I call:
pacmd load-module module-alsa-sink device=hw:2 control='MOST Mixer'

syslog says:

Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] reserve-wrap.c: Successfully acquired reservation lock on device 'Audio2'
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] reserve-wrap.c: Successfully create reservation lock monitor for device 'Audio2'
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] alsa-util.c: Trying hw:2 with SND_PCM_NO_AUTO_FORMAT ...
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] alsa-util.c: Managed to open hw:2
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] alsa-util.c: cannot disable ALSA period wakeups
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] alsa-util.c: Maximum hw buffer size is 140 ms
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] alsa-util.c: Set buffer size first (to 96000 samples), period size second (to 96000 samples).
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] alsa-util.c: Device hw:2 doesn't support 44100 Hz, changed to 48000 Hz.
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] alsa-util.c: Device hw:2 doesn't support 2 channels, changed to 6.
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] alsa-util.c: ALSA period wakeups were not disabled
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] alsa-sink.c: Successfully opened device hw:2.
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] alsa-sink.c: Successfully enabled mmap() mode.
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] alsa-sink.c: Successfully enabled timer-based scheduling mode.
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] alsa-util.c: Successfully attached to mixer 'hw:2'
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] alsa-mixer.c: Probing path 'MOST Mixer'
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] alsa-mixer.c: Probe of element 'MOST Mixer' succeeded (volume=0, switch=0, enumeration=0).
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] alsa-sink.c: Probed mixer path MOST Mixer:
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] alsa-mixer.c: Path MOST Mixer ((null)), direction=1, priority=0, probed=yes, supported=yes, has_mute=no, has_volume=no, has_dB=no, min_volume=0, max_volume=0, min_dB=inf, max_dB=-inf
Dec 21 15:29:49 kar-dk-m21106-m1 kernel: [ 1647.611918] most-snd: volume_info()
Dec 21 15:29:49 kar-dk-m21106-m1 kernel: [ 1647.611923] most-snd: volume_get()
Dec 21 15:29:49 kar-dk-m21106-m1 kernel: [ 1647.611928] most-snd: volume_info()
Dec 21 15:29:49 kar-dk-m21106-m1 kernel: [ 1647.611930] most-snd: volume_get()
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] module-device-restore.c: Restoring volume for sink alsa_output.hw_2.
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] module-device-restore.c: Restored volume: 0:  80% 1:  80% 2:  80% 3:  80% 4:  80% 5:  80%
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] module-device-restore.c: Restoring mute state for sink alsa_output.hw_2.
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] sink.c: Default and alternate sample rates are the same.
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] sink.c: Created sink 2 "alsa_output.hw_2" with sample spec s16le 6ch 48000Hz and channel map front-left,front-right,rear-left,rear-right,front-center,lfe
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] sink.c:     alsa.resolution_bits = "16"
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] sink.c:     device.api = "alsa"
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] sink.c:     device.class = "sound"
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] sink.c:     alsa.class = "generic"
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] sink.c:     alsa.subclass = "generic-mix"
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] sink.c:     alsa.name = "most_snd_tx"
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] sink.c:     alsa.id = "mdev0-ep01"
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] sink.c:     alsa.subdevice = "0"
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] sink.c:     alsa.subdevice_name = "subdevice #0"
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] sink.c:     alsa.device = "0"
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] sink.c:     alsa.card = "2"
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] sink.c:     alsa.card_name = "Microchip MOST:2"
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] sink.c:     alsa.long_card_name = "Microchip MOST:2 at usb_device 1-4:1.2, ch 0"
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] sink.c:     device.bus_path = "/devices/virtual/sound/card2"
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] sink.c:     sysfs.path = "/devices/virtual/sound/card2"
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] sink.c:     device.string = "hw:2"
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] sink.c:     device.buffering.buffer_size = "80640"
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] sink.c:     device.buffering.fragment_size = "5040"
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] sink.c:     device.access_mode = "mmap+timer"
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] sink.c:     device.description = "Microchip MOST:2"
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] sink.c:     alsa.mixer_name = "MOST Mixer"
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] sink.c:     device.icon_name = "audio-card"
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] source.c: Created source 3 "alsa_output.hw_2.monitor" with sample spec s16le 6ch 48000Hz and channel map front-left,front-right,rear-left,rear-right,front-center,lfe
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] source.c:     device.description = "Monitor of Microchip MOST:2"
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] source.c:     device.class = "monitor"
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] source.c:     device.icon_name = "audio-input-microphone"
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] alsa-sink.c: Using 16.0 fragments of size 5040 bytes (8.75ms), buffer size is 80640 bytes (140.00ms)
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] alsa-sink.c: Time scheduling watermark is 6.12ms
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] alsa-sink.c: hwbuf_unused=0
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] alsa-sink.c: setting avail_min=6427
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] alsa-mixer.c: Activating path MOST Mixer
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] alsa-mixer.c: Path MOST Mixer ((null)), direction=1, priority=0, probed=yes, supported=yes, has_mute=no, has_volume=no, has_dB=no, min_volume=0, max_volume=0, min_dB=inf, max_dB=-inf
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] alsa-sink.c: Driver does not support hardware volume control, falling back to software volume control.
Dec 21 15:29:49 kar-dk-m21106-m1 pulseaudio[1940]: [pulseaudio] alsa-sink.c: Driver does not support hardware mute control, falling back to software mute control. 



I appreciate any hint that helps to get hw volume control running.
Can you help?

Best regards
Peter