I'd like to thank people who helped me with this on and offlist, and also note two sources that describe this problem and solutions to it. They are both really good documents.
The Securing Debian Manual at FAQ 11.1.11 http://www.debian.org/doc/manuals/securing-debian-howto/ch11.en.html describes how to fix the problem temporarily with dmesg -n or permanently by altering startup files. The Debian Reference gives the same advice at http://www.debian.org/doc/manuals/reference/ch-tips.en.html#s8.6.8 I've tried it out, and it seems to work. Note that higher level numbers are for *less* serious warnings, and that the dmesg man page is slightly confused on this point (or at least confusing). -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]