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 1.0.14

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 5.10.0.6120. Problem EXISTS.

e) Windows XP drivers from Asus website for SiS 7012 version 5.12.1.38. Problem DOES NOT EXIST.

f) Windows XP drivers from CMedia website (http://www.cmedia.com.tw) version 5.12.1.39. Problem DOES NOT EXIST.

g) Windows XP drivers from CMedia forum (http://www.cmedia.com.tw/forums) version 5.12.1.51. 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...

Takashi