[alsa-devel] Intel HD: ALC662 noise-bug on FitPC2i

Wed Dec 12 08:26:08 CET 2012

Hi list

I have tried to access the bugtracker at
https://bugtrack.alsa-project.org/alsa-bug for a while without luck, so
now I will try to post the bug here...

Problem:
When recording, audible clicking sounds are present in the resulting
audio data.

Analysis:
When recording at 48kHz 1024 samples per channel are returned by the
snd_pcm_readi function.
I made a test app that wrote zeros into the first 20 samples of each
recorded buffer in order to 'mark' the beggining of each buffer in the
output file and it appears that the clicking noise come from buffer
corruption at position 1024-160 samples (160 samples from the end of
the buffer).

The corruption are composed of approximately 10 samples, and the
nature of the corrupted values are such that they could come from an
earlier buffer (the corrupted data resemble wav forms).

Sometimes only a single sample seem to be corrupted (see
wavform3.png), but sometimes several (see wavform1.png and
wavform2.png).

Usually the number of corrupted samples are the same for both channels.

A sample recording produced by the command:
arecord -c 2 -t raw -f S16_LE -r 48000 --disable-resample -d 10
alc662-noise-bug.raw
The resulting file can be fetched at
 http://www.aasimon.org/public/alc662-noise-bug.raw (too big to send by
email)

Hardware:
Fit-PC2i (Atom Z530).
Intel HD driver with ALC662 codec.

Kernel (uname -a):
Linux InterCom 3.2.1-gentoo-r2-fitpc2i #1 SMP Tue Dec 11 09:10:23 i686
Intel(R) Atom(TM) CPU Z530 @ 1.60GHz GenuineIntel GNU/Linux

Alsa-lib and utils used were v.1.0.24, but tests with kernel-3.5.7 and
alsa-lib/utils-1.0.25 has also been performed with similiar results.

Kernel compiled with asound debug (from .config):
CONFIG_SND_DEBUG=y
CONFIG_SND_DEBUG_VERBOSE=y
CONFIG_SND_PCM_XRUN_DEBUG=y

Log output with "echo 127 > /proc/asound/card0/pcm0c/xrun_debug":

Command run:
(arecord -c 2 -t raw -r 48000 -d 0.1 out.raw &) ; sleep 0.015; killall
arecord

Dec 10 15:58:46 InterCom kernel: [ 1733.745094] hda-intel:
azx_pcm_prepare: bufsize=0x10000, format=0x21
Dec 10 15:58:46 InterCom kernel: [ 1733.745109] hda_codec_setup_stream:
NID=0x8, stream=0x2, channel=0, format=0x21
Dec 10 15:58:46 InterCom kernel: [ 1733.749510] hwptr_update:
pcmC0D0c:0: pos=209/1024/8192, hwptr=209/0/209/0
Dec 10 15:58:46 InterCom kernel: [ 1733.749553] hwptr_update:
pcmC0D0c:0: pos=212/1024/8192, hwptr=3/209/212/0
Dec 10 15:58:46 InterCom kernel: [ 1733.749609] hwptr_update:
pcmC0D0c:0: pos=214/1024/8192, hwptr=2/212/214/0
Dec 10 15:58:46 InterCom kernel: [ 1733.749645] hwptr_update:
pcmC0D0c:0: pos=216/1024/8192, hwptr=2/214/216/0
Dec 10 15:58:46 InterCom kernel: [ 1733.749664] hwptr_update:
pcmC0D0c:0: pos=217/1024/8192, hwptr=1/216/217/0
Dec 10 15:58:46 InterCom kernel: [ 1733.749694] hwptr_update:
pcmC0D0c:0: pos=219/1024/8192, hwptr=2/217/219/0
Dec 10 15:58:46 InterCom kernel: [ 1733.749719] hwptr_update:
pcmC0D0c:0: pos=220/1024/8192, hwptr=1/219/220/0
Dec 10 15:58:46 InterCom kernel: [ 1733.749738] hwptr_update:
pcmC0D0c:0: pos=221/1024/8192, hwptr=1/220/221/0
Dec 10 15:58:46 InterCom kernel: [ 1733.749767] hwptr_update:
pcmC0D0c:0: pos=222/1024/8192, hwptr=1/221/222/0
Dec 10 15:58:46 InterCom kernel: [ 1733.749793] hwptr_update:
pcmC0D0c:0: pos=223/1024/8192, hwptr=1/222/223/0
Dec 10 15:58:46 InterCom kernel: [ 1733.749813] hwptr_update:
pcmC0D0c:0: pos=224/1024/8192, hwptr=1/223/224/0
Dec 10 15:58:46 InterCom kernel: [ 1733.749841] hwptr_update:
pcmC0D0c:0: pos=226/1024/8192, hwptr=2/224/226/0
Dec 10 15:58:46 InterCom kernel: [ 1733.749867] hwptr_update:
pcmC0D0c:0: pos=227/1024/8192, hwptr=1/226/227/0
Dec 10 15:58:46 InterCom kernel: [ 1733.749887] hwptr_update:
pcmC0D0c:0: pos=228/1024/8192, hwptr=1/227/228/0
Dec 10 15:58:46 InterCom kernel: [ 1733.749914] hwptr_update:
pcmC0D0c:0: pos=229/1024/8192, hwptr=1/228/229/0
Dec 10 15:58:46 InterCom kernel: [ 1733.749940] hwptr_update:
pcmC0D0c:0: pos=230/1024/8192, hwptr=1/229/230/0
Dec 10 15:58:46 InterCom kernel: [ 1733.749961] hwptr_update:
pcmC0D0c:0: pos=231/1024/8192, hwptr=1/230/231/0
Dec 10 15:58:46 InterCom kernel: [ 1733.749989] hwptr_update:
pcmC0D0c:0: pos=233/1024/8192, hwptr=2/231/233/0
Dec 10 15:58:46 InterCom kernel: [ 1733.752935] hwptr_update:
pcmC0D0c:0: pos=374/1024/8192, hwptr=141/233/374/0
Dec 10 15:58:46 InterCom kernel: [ 1733.752964] hwptr_update:
pcmC0D0c:0: pos=376/1024/8192, hwptr=2/374/376/0
Dec 10 15:58:46 InterCom kernel: [ 1733.753002] hwptr_update:
pcmC0D0c:0: pos=377/1024/8192, hwptr=1/376/377/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754067] hwptr_update:
pcmC0D0c:0: pos=428/1024/8192, hwptr=51/377/428/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754092] hwptr_update:
pcmC0D0c:0: pos=430/1024/8192, hwptr=2/428/430/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754129] hwptr_update:
pcmC0D0c:0: pos=431/1024/8192, hwptr=1/430/431/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754156] hwptr_update:
pcmC0D0c:0: pos=433/1024/8192, hwptr=2/431/433/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754175] hwptr_update:
pcmC0D0c:0: pos=434/1024/8192, hwptr=1/433/434/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754204] hwptr_update:
pcmC0D0c:0: pos=435/1024/8192, hwptr=1/434/435/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754230] hwptr_update:
pcmC0D0c:0: pos=436/1024/8192, hwptr=1/435/436/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754250] hwptr_update:
pcmC0D0c:0: pos=437/1024/8192, hwptr=1/436/437/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754278] hwptr_update:
pcmC0D0c:0: pos=439/1024/8192, hwptr=2/437/439/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754304] hwptr_update:
pcmC0D0c:0: pos=440/1024/8192, hwptr=1/439/440/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754324] hwptr_update:
pcmC0D0c:0: pos=441/1024/8192, hwptr=1/440/441/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754351] hwptr_update:
pcmC0D0c:0: pos=442/1024/8192, hwptr=1/441/442/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754377] hwptr_update:
pcmC0D0c:0: pos=443/1024/8192, hwptr=1/442/443/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754398] hwptr_update:
pcmC0D0c:0: pos=444/1024/8192, hwptr=1/443/444/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754425] hwptr_update:
pcmC0D0c:0: pos=446/1024/8192, hwptr=2/444/446/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754450] hwptr_update:
pcmC0D0c:0: pos=447/1024/8192, hwptr=1/446/447/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754472] hwptr_update:
pcmC0D0c:0: pos=448/1024/8192, hwptr=1/447/448/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754501] hwptr_update:
pcmC0D0c:0: pos=449/1024/8192, hwptr=1/448/449/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754525] hwptr_update:
pcmC0D0c:0: pos=450/1024/8192, hwptr=1/449/450/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754545] hwptr_update:
pcmC0D0c:0: pos=451/1024/8192, hwptr=1/450/451/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754575] hwptr_update:
pcmC0D0c:0: pos=453/1024/8192, hwptr=2/451/453/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754599] hwptr_update:
pcmC0D0c:0: pos=454/1024/8192, hwptr=1/453/454/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754618] hwptr_update:
pcmC0D0c:0: pos=455/1024/8192, hwptr=1/454/455/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754647] hwptr_update:
pcmC0D0c:0: pos=456/1024/8192, hwptr=1/455/456/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754673] hwptr_update:
pcmC0D0c:0: pos=458/1024/8192, hwptr=2/456/458/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754691] hwptr_update:
pcmC0D0c:0: pos=458/1024/8192, hwptr=0/458/458/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754718] hwptr_update:
pcmC0D0c:0: pos=460/1024/8192, hwptr=2/458/460/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754744] hwptr_update:
pcmC0D0c:0: pos=461/1024/8192, hwptr=1/460/461/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754764] hwptr_update:
pcmC0D0c:0: pos=462/1024/8192, hwptr=1/461/462/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754791] hwptr_update:
pcmC0D0c:0: pos=463/1024/8192, hwptr=1/462/463/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754817] hwptr_update:
pcmC0D0c:0: pos=464/1024/8192, hwptr=1/463/464/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754837] hwptr_update:
pcmC0D0c:0: pos=465/1024/8192, hwptr=1/464/465/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754865] hwptr_update:
pcmC0D0c:0: pos=467/1024/8192, hwptr=2/465/467/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754889] hwptr_update:
pcmC0D0c:0: pos=468/1024/8192, hwptr=1/467/468/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754910] hwptr_update:
pcmC0D0c:0: pos=469/1024/8192, hwptr=1/468/469/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754940] hwptr_update:
pcmC0D0c:0: pos=470/1024/8192, hwptr=1/469/470/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754964] hwptr_update:
pcmC0D0c:0: pos=472/1024/8192, hwptr=2/470/472/0
Dec 10 15:58:46 InterCom kernel: [ 1733.754983] hwptr_update:
pcmC0D0c:0: pos=472/1024/8192, hwptr=0/472/472/0
Dec 10 15:58:46 InterCom kernel: [ 1733.761111]
hda_codec_cleanup_stream: NID=0x8

Thank you in advance.

Kind regards
Bent Bisballe Nyeng

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