Ok, please file a separate bug regarding initrd (same source package, linux-source-2.6.15). I'm closing this bug per your reports, thanks.
** Changed in: linux-source-2.6.15 linux-image-2.6.15-18-k7 (Ubuntu)
Status: Needs Info => Fix Released
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static in sound output with alc880
https://launchpad.net/malone/bugs/34645