Bug#275572: kernel-image-2.6.8-1-k7-smp: serial port doesn't work when booted with cable connected to UPS

[Peter Cordes <peter@cordes.ca>]

Package: kernel-image-2.6.8-1-k7-smp
Version: 2.6.8-3
Severity: normal

 I have a Tyan S2881, BIOS v2.04 (dual opteron).  When the machine boots
with the serial port connected to my PowerWare 5125 1500RM UPS, the kernel
doesn't detect that serial port (ttyS0).  When I boot with the cable
disconnected, the port is detected just fine.  (And nut can be started and
will work fine if the cable is later connected).

 When I boot with the cable connected, setserial says the port has the right
IO and IRQ (0x3f8/IRQ4), but it says unknown uart.  
  setserial /dev/ttyS0 uart 16500A
makes the kernel say "LSR safety check engaged".

 This obviously makes it impossible to leave the machine unattended and have
UPS support for this dumb UPS.  (The online manual from powerware's site has
the pinout for the dumb signalling, in case the kernel serial driver is
getting confused because of the UPS keeping one of the lines high or
something.)

 I haven't had time to try different kernel versions...

 Thanks,

-- System Information:
Debian Release: 3.1
  APT prefers testing
  APT policy: (990, 'testing'), (500, 'unstable')
Architecture: i386 (i686)
Kernel: Linux 2.6.8-1-k7-smp
Locale: LANG=C, LC_CTYPE=C

Versions of packages kernel-image-2.6.8-1-k7-smp depends on:
ii  coreutils [fileutils]         5.2.1-2    The GNU core utilities
ii  initrd-tools                  0.1.74     tools to create initrd image for p
ii  module-init-tools             3.1-pre5-7 tools for managing Linux kernel mo

-- no debconf information