tag 502140 patch thank you i have developed a preinst for libpam-modules that will wait for xscreensaver to be deactivated before allowing it to begin its upgrade. then to prevent the screensaver from reactivating, it will send the deactivate command every 30 seconds until dpkg is unlocked (meaning the upgrade is done).
this should resolve the problem...i think.
libpam-modules.preinst
Description: application/shellscript
