I tried to recompile my kernel with "Power management options -> APM -> APM BIOS support -> Enable PM at boot time" option enabled and everything went well without acpi=force, which I was obliged to use in order to avoid hangs. Since this affects Edgy too, I think this option should be turned on in newer releases of kernel packages: older PCs which does not enable ACPI by default might suffer from this behaviour.
** Changed in: linux-source-2.6.15 (Ubuntu) Status: Unconfirmed => Confirmed -- Kernel hangs on USB-devices without panic https://launchpad.net/bugs/50610 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs