The sound initialization scripts provided with Mandriva Linux 2009 activate the Analog Loopback channel when it is present. This channel is present on most audio chipsets supported by the snd-hda-intel driver, which are commonly used on recent systems. When active, this channel plays back the sound received by the line-in and mic-in channels. If nothing is actually connected to these channels, this can result in an unpleasant loud noise over the speakers or headphones connected to the line-out or speaker-out connector. This update adjusts the sound initialization scripts to mute this channel by default. Unfortunately, this change will not be applied automatically on already-installed systems, as existing settings are automatically stored at shutdown and re-applied at startup on Mandriva Linux. If you are suffering from this issue, then you can run the command "reset_sound" as root after installing this update, and it should resolve the issue. Alternatively, you can simply disable / mute the Analog Loopback channel yourself, using a mixer application.