[GA-MA770T-UD3P, Realtek ALC888] Distorted crackling noise when used with low latency clients

[Kevin Israel]

Description:
In certain applications, including FluidSynth (and sometimes VLC) yet not Rhythmbox, the onboard audio of the Gigabyte GA-MA770T-UD3P (rev. 1.0) motherboard "sort of" works; there is a loud, distorted crackling noise mixed with the audio. A different, more "ordinary" crackle occurs in audio recorded using Sound Recorder and Skype.

Both playback and recording in 12.04 and 12.10 are affected. I do not remember how well the audio worked in 11.10. Sometimes, after some time has elapsed, or when other applications (e.g. Flash plugin) are opened, the crackle goes away. In fact, it did go away a couple seconds after I clicked Apport's "Close" button after reproducing the bug using the steps below.

Workarounds I tried:
Upgrading to the latest DKMS driver snapshot (dkms-hda - 0.201212071018~quantal1) made no difference. "position_fix=1" made no difference either (perhaps that was already in use). "position_fix=2" removed the crackle but caused a sound I can best describe as "CD skipping".

Adding the "tsched=0" setting to /etc/pulse/default.pa did work for playback. However, this did not fix recording in the aforementioned applications.

Steps to reproduce (on my hardware):
1. sudo apt-get install fluid-soundfont-gm fluid-soundfont-gs fluidsynth
2. pulseaudio -k
3. fluidsynth -nia pulseaudio /usr/share/sounds/sf2/*.sf2 foo.mid

fluidsynth -nia alsa is also problematic, EXCEPT when I specify "-o 'audio.alsa.device=hw'".

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: alsa-base 1.0.25+dfsg-0ubuntu3
ProcVersionSignature: Ubuntu 3.5.0-19.30-generic 3.5.7
Uname: Linux 3.5.0-19-generic x86_64
ApportVersion: 2.6.1-0ubuntu6
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC1: ki 2598 F.... pulseaudio
 /dev/snd/controlC0: ki 2598 F.... pulseaudio
 /dev/snd/pcmC0D0p: ki 2598 F...m pulseaudio
Date: Fri Dec 7 22:31:35 2012
InstallationDate: Installed on 2012-03-13 (269 days ago)
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111011)
MarkForUpload: True
PackageArchitecture: all
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: alsa-driver
Symptom: audio
Symptom_AlsaPlaybackTest: ALSA playback test through plughw:SB successful
Symptom_Card: Built-in Audio - HDA ATI SB
Symptom_Jack: Green Line Out, Rear
Symptom_PulsePlaybackTest: PulseAudio playback test successful
Symptom_Type: Underruns, dropouts, or "crackling" sound
Title: [GA-MA770T-UD3P, Realtek ALC888, Green Line Out, Rear] Underruns, dropouts or crackling sound
UpgradeStatus: Upgraded to quantal on 2012-12-08 (0 days ago)
dmi.bios.date: 03/22/2011
dmi.bios.vendor: Award Software International, Inc.
dmi.bios.version: F12
dmi.board.name: GA-MA770T-UD3P
dmi.board.vendor: Gigabyte Technology Co., Ltd.
dmi.chassis.type: 3
dmi.chassis.vendor: Gigabyte Technology Co., Ltd.
dmi.modalias: dmi:bvnAwardSoftwareInternational,Inc.:bvrF12:bd03/22/2011:svnGigabyteTechnologyCo.,Ltd.:pnGA-MA770T-UD3P:pvr:rvnGigabyteTechnologyCo.,Ltd.:rnGA-MA770T-UD3P:rvr:cvnGigabyteTechnologyCo.,Ltd.:ct3:cvr:
dmi.product.name: GA-MA770T-UD3P
dmi.sys.vendor: Gigabyte Technology Co., Ltd.

[Raymond (superquad-vortex2)]

>>fluidsynth -nia alsa is also problematic, EXCEPT when I specify "-o 'audio.alsa.device=hw'".

do you mean those apllication which require low latency only work with alsa device hw

pulseaudio or alsa pulse plugin does not work well wiyth those low latency application ?

[Kevin Israel (pleasestand)]

Raymond: Yes, I do suspect this is a problem with "glitch-free" PulseAudio output when applications ask for low latency, and it definitely happened with both FluidSynth and VLC on both 12.04 and 12.10.

On 12.10, I can only reproduce the problem in VLC using its PulseAudio output module, through which it requests "0.00 ms" latency - NOT using its ALSA output module set to "Playback/recording through the PulseAudio sound server". VLC was not misbehaving at the time Symptom_PulseAudioLog.txt was captured, because I had already switched it to the ALSA setting when I was running 12.04.

Here is a PulseAudio "-vvvv" log of this. The crackling noise stopped at about the time "alsa-sink.c: Underrun!" appeared following all the "memblock.c: Pool full" and "flist.c: pulsecore/memblockq.c: list_items flist is full (don't worry)" lines. This was about a minute after I started a video playing. (Unfortunately, this particular log file does not have timestamps, although the problem is easy to reproduce if necessary.)

Recording might have only been an issue in 12.04, which did not even seem to detect my input jacks correctly. Aside from the usual noise, I seem to have no problem with my mic input right now. So we should probably focus on the playback issue.

[David Henningsson (diwic)]

fluidsynth suggests an extremely low latency by default; if you just want to play back a midi file, please use e g " -z 4096" as parameter to fluidsynth.

[Kevin Israel (pleasestand)]

David: Thanks, the -z FluidSynth setting works. However, FluidSynth is not the only affected program. In particular, I shouldn't have to change VLC to use its ALSA output module instead of its PulseAudio module, which is the default. If my hardware can't handle low latency playback, PulseAudio shouldn't attempt it at all. If there's a bug in the driver, the driver should be fixed.

[David Henningsson (diwic)]

Sure, I don't deny that there's a bug here. There's also bug 751265 for the VLC - PulseAudio problems.

[Daniel van Vugt (vanvugt)]

Thank you for reporting this bug to Ubuntu.
Ubuntu 12.10 (quantal) reached end-of-life on May 16, 2014.

See this document for currently supported Ubuntu releases:
https://wiki.ubuntu.com/Releases

We appreciate that this bug may be old and you might not be interested in discussing it any more. But if you are then please upgrade to the latest Ubuntu version and re-test.

[Launchpad Janitor (janitor)]

[Expired for pulseaudio (Ubuntu) because there has been no activity for 60 days.]