I confirm that the increasing sound volume problem is due to linux-backports-modules-2.6.22-14-generic_2.6.22-14.11UNRELEASED_i386.deb. I replaced it by linux-backports-modules-2.6.22-14-generic (v 2.6.22-14.10) and now my sound volume is stable.
I confirm that the increasing sound volume problem is due to linux-backports -modules- 2.6.22- 14-generic_ 2.6.22- 14.11UNRELEASED _i386.deb. I replaced it by linux-backports -modules- 2.6.22- 14-generic (v 2.6.22-14.10) and now my sound volume is stable.