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miskoala

Member

Registered: 2012-03-27

Posts: 10

ALSA Intel HDA Spdif pops

Hi

I hear pops in speakers when start playback and start/stop seeking forward or backward in tracks in mpd with ALSA output.
I use spdif out with Intel HDA ALC662, connected to 2 pins on motherboard (Intel D945GSEJT) by coax cable

Only one pop when starting track, sometimes louder sometimes quieter sometimes none (can't notice pattern)

But this is annoying

Play without pops with Pulseaudio but I want to avoid this (I don't need Pulseaudio here, I don't want to resample stuff before sending it to spdif output)

Also tested PCI soundcard ESI Juli@ with spdif (coax) output - there are no pops when start playback and start/stop seek forward or backward in tracks, played smoothly (mpd with alsa output same as for Intel)

It must be Alsa driver related thing, right?

uname -r

3.2.13-1-ARCH

pacman -Q alsa-lib

alsa-lib 1.0.25-1

lspci -v

00:1b.0 Audio device: Intel Corporation N10/ICH 7 Family High Definition Audio Controller (rev 02)
        Subsystem: Intel Corporation Device d615
        Flags: bus master, fast devsel, latency 0, IRQ 46
        Memory at cff00000 (64-bit, non-prefetchable) [size=16K]
        Capabilities: <access denied>
        Kernel driver in use: snd_hda_intel

05:00.0 Multimedia audio controller: VIA Technologies Inc. VT1720/24 [Envy24PT/HT] PCI Multi-Channel Audio Controller (rev 01)
        Subsystem: Device 3031:4553
        Flags: bus master, medium devsel, latency 32, IRQ 20
        I/O ports at d080 [size=32]
        I/O ports at d000 [size=128]
        Capabilities: <access denied>
        Kernel driver in use: snd_ice1724

aplay -l

**** List of PLAYBACK Hardware Devices ****
card 0: Intel [HDA Intel], device 0: ALC662 rev1 Analog [ALC662 rev1 Analog]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: Intel [HDA Intel], device 1: ALC662 rev1 Digital [ALC662 rev1 Digital]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: Juli [ESI Juli@], device 0: ICE1724 [ICE1724]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: Juli [ESI Juli@], device 1: ICE1724 IEC958 [ICE1724 IEC958]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

cat /etc/modprobe.d/modprobe.conf

blacklist pcspkr
blacklist padlock-sha
blacklist r8169

alias net-pf-10 off

options snd-hda-intel power_save=0
options snd-hda-intel power_save_controller=N

mpd.conf

audio_output {
        type            "alsa"
        name            "Alsa"
        device          "hw:0,1"
        use_mmap        "yes" 
        auto_resample   "no"
        auto_channels   "no"
        auto_format     "no"
        mixer_type      "software"
}

Should I provide more info?
Can I do something with that? (or should I report it as a bug on alsa page?)

brebs

Member

Registered: 2007-04-03

Posts: 3,742

Re: ALSA Intel HDA Spdif pops

The difference is that Pulseaudio keeps the device open all the time.

It would be interesting to write a tiny C program that opens up dmix, then does zilch except stay running.

miskoala

Member

Registered: 2012-03-27

Posts: 10

Re: ALSA Intel HDA Spdif pops

but I don't have this pops with ESI Juli@ Spdif when playing tracks in mpd with Alsa output (hw:0,1 in mpd.conf)
that's why I was thinking there shouldn't be pops on ALC662 Spdif when playing tracks in mpd with Alsa output (hw:1,1 in mpd.conf)

:>