[alsa-devel] High-pitched noise on output from cmi9739 (snd_intel8x0)
tiwai at suse.de
Mon Jul 2 18:29:12 CEST 2007
At Sat, 30 Jun 2007 11:57:43 +0100,
j t wrote:
> Hi all.
> I have a cmi9739 (sis7012) built into an asus k7s8x motherboard which
> produces a quiet but noticeable noise on top of the regular output
> (the noise only occurs during playback).
> I logged a bug to alsa's bugtrack:
> (https://bugtrack.alsa-project.org/alsa-bug/view.php?id=2288) about a
> year ago, but unfortunately I still have the problem with alsa release
> To try to find out what's going on, I tried using seven (7) different
> drivers for this soundcard (both Linux and Windows XP) to find out
> when the problem occurs. Here's the results:
> a) Alsa (snd_intel8x0) version 1.0.14 under Ubuntu 7.10 alpha 2. Problem EXISTS.
> b) OSS 4Front Opensound v4.1 (v4.1test0-070624). Problem EXISTS
> c) CMedia Linux OSS driver cmaudio-070 (from
> http://www.cmedia.com.tw). Problem EXISTS.
> d) Windows XP "built-in" driver for SiS 7012 version 220.127.116.1120.
> Problem EXISTS.
> e) Windows XP drivers from Asus website for SiS 7012 version
> 18.104.22.168. Problem DOES NOT EXIST.
> f) Windows XP drivers from CMedia website (http://www.cmedia.com.tw)
> version 22.214.171.124. Problem DOES NOT EXIST.
> g) Windows XP drivers from CMedia forum
> (http://www.cmedia.com.tw/forums) version
> 126.96.36.199. Problem DOES NOT EXIST.
> Given that the problem does not happen with three out of the seven
> drivers, I assume it's a driver problem. Is there anything that I can
> do debug this further?
It's pretty hard to debug, I'm afraid, unless we know _what_ is the
cause of the noise. Possibly we need some quirks for PCI setup
(e.g. adjust latency via setpci), or it might be a confliction of
cpufreq (disable the kernel config, or even try HZ=100), or any
unknown hardware features...
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