Same problem here, with an HDA nVidia card (snd_hda_intel)
To me, the problem first occours when I modify the volume via the panel applet.
Also, I noticed that the pitch noise seems variate in strength at dfferent volume values.
Tried linux-backports-modules-alsa-2.6.31-15.50 but same problem. I'll try to boot in 2.6.31-14 and see if problem occours
Same problem here, with an HDA nVidia card (snd_hda_intel)
To me, the problem first occours when I modify the volume via the panel applet.
Also, I noticed that the pitch noise seems variate in strength at dfferent volume values.
Tried linux-backports -modules- alsa-2. 6.31-15. 50 but same problem.
I'll try to boot in 2.6.31-14 and see if problem occours