How to hotswap the UltraBase

Introduction

Here is how I set up an X22 to allow hot ejection/removal of the ultrabase. See also this related page for the UltraBay. These instructions are well-tested, but ymmv.

Features

• Uses lt_hotswap to preserve DMA on re-insert
• Idiot-proof (relatively)
• Scripts also work without lt_hotswap (using the older way, idectl).

System

• X22 thinkpad + ultrabase + DVD-R
• lt_hotswap version 0.3.9
• kernel-2.6.17.1
• xorg 6.9.0

Files

rc.local

First, make sure the lt_hotswap module is loaded. Add this to /etc/rc.local (or use modprobe.preload, if you prefer)

echo "Loading lt_hotswap module"
modprobe lt_hotswap hdc_dock=1

/etc/acpi/events/lths

Disable the existing lths script. Here is the modified /etc/acpi/events/lths:

# Call the LTHS script
event=lths.*
#action=/usr/local/sbin/lths.sh %e
action=echo "Not invoking lths.sh; this is now done by the ultrabase_eject and insert scripts instead."

/etc/acpi/events/ultrabase_eject

Respond to an ultrabase eject event. Here is /etc/acpi/events/ultrabase_eject

#Ultrabase eject button has been pressed
#We can be triggered by an ibm/bay event if NOT using lt_hotswap, or an lt_hotswap event if we are.
event=ibm/bay.MSTR.00000003.00000000
event=lths.MSTR.00000003.00000000
action=/etc/acpi/actions/ultrabase_eject.sh

/etc/acpi/events/ultrabase_insert

Respond to an ultrabase insert event. Here is /etc/acpi/events/ultrabase_insert

#Ultrabase has been re-inserted
#We can be triggered by an ibm/bay event if NOT using lt_hotswap, or an lt_hotswap event if we are.
event=ibm/bay.MSTR.00000001.00000000
event=lths.MSTR.00000001.00000000
action=/etc/acpi/actions/ultrabase_insert.sh

/etc/acpi/actions/ultrabase_eject.sh

This is the actual script which does the ejection. It is /etc/acpi/actions/ultrabase_eject.sh

• Note the dependency on cddb-id.

#!/bin/bash
echo "syncing disks for safety"
sync

echo "Unregistering IDE interface for CDROM and preparing to eject."

#Note: the BIOS will already deal with the ultrabay LED (number 3). It will:
#  * turn it on when the bay is loaded
#  * turn it off when the bay is unloaded
#  * blink it when it is waiting between an eject request and an eject. (Linux never takes long enough to see this!)

#What if there is a disk in the drive?
#Case 1: there is an umounted CDROM, or an AudioCD/DVD which is NOT playing.
# => It's OK to proceed.

#Case 2: there is a mounted CDROM. 
# => we MUST unmount it, or give up on ejecting.
if grep hdc /proc/mounts >/dev/null; then
       echo "There is a mounted filesystem on /dev/hdc. Trying to unmount it"
       umount /dev/hdc
       if [ $? == 0 ]; then
               echo "Successfully unmounted the CDROM."
       else
               echo "The CDROM is busy; can't unmount. Do not try to undock."
               echo 9 > /proc/acpi/ibm/beep   #This is an "unhappy, warning beep"
               exit 1
       fi
fi

#Case 3: there is a AudioCD/DVD which is currently playing.
#How do we detect this? It could be just using cdplay (which has no associated process)
#The following methd is ugly, and it requires the cddb-id program. However, it does work.
#Assuming that we have already ruled out a mounted filesystem, then...
CDDBID=$(cddb-id /dev/hdc 2>/dev/null)
if [ -n "$CDDBID" ]; then
       echo "There is a CD in the drive. Ejecting it"
       eject /dev/hdc   #Buglet: we don't necessarily want to eject the disk; we just want to be sure it has stopped playing.
fi

#We're now OK to proceed.
if /sbin/lsmod | grep lt_hotswap > /dev/null ; then
       echo "We are using lt_hotswap"
        #Eject the bay using lths.
       echo -n "MSTR eject" > /proc/acpi/lths
else
       echo "We are not using lt_hotswap. Do it the old way with idectl."
        #Unregister IDE interface 1. This WILL cause a kernel panic if there is anything in the drive!
       idectl 1 off
        #Tell the thinkpad the bay is to be ejected
       echo eject > /proc/acpi/ibm/bay
fi

#Beep happily
echo 6 > /proc/acpi/ibm/beep
echo "OK to undock"

/etc/acpi/actions/ultrabase_insert.sh

This script is called on insertion. It is /etc/acpi/actions/ultrabase_insert.sh

#!/bin/bash
echo "Ultrabase has been inserted. Re-registering IDE interface for CDROM."

if /sbin/lsmod | grep lt_hotswap > /dev/null ; then
       echo "We are using lt_hotswap"
       echo "Enabling DMA on /dev/hdc"
       hdparm -d 1 -u 1 -c 1 /dev/hdc

       #LTHS already beeps; no beep required here.
else
       echo "We are not using lt_hotswap. Do it the old way with idectl."

       #Register IDE interface 1
       idectl 1 rescan
       #Turn DMA on again. But this is probably a vain attempt; it will fail unless we are using lt_hotswap.
       sleep 2
       hdparm -d1 /dev/hdc || echo "WARNING: DMA cannot be re-enabled for hdc after insert. You'll have to reboot for now."

       #Beep happily
       echo 6 > /proc/acpi/ibm/beep
fi

echo "Redocked successfully"
echo "Note: KDE's volume manager might not work anymore with the CD/DVD drive."

Debugging

• The easiest way to check what is happening is:

tail -f /var/log/acpid

• Remember, after modifying anything in /etc/acpi/events, to reload the acpid rules:

killall -HUP acpid

• Note that stdout from all scripts ends up in /var/log/acpid. But to communicate a message with the user, it's best to use either the various thinkpad beeps, or perhaps the thinklight.

• Note: idectl and lt_hotswap really don't get along together. You will lock the system.