diff -Nru hotkey-setup-0.1/debian/changelog hotkey-setup-0.1/debian/changelog
--- hotkey-setup-0.1/debian/changelog	2008-09-09 20:57:49.000000000 +0100
+++ hotkey-setup-0.1/debian/changelog	2008-10-13 13:02:16.000000000 +0100
@@ -1,3 +1,21 @@
+hotkey-setup (0.1-23ubuntu6) intrepid; urgency=low
+
+  * Revert 0.1-23ubuntu4 and use a different method to set the hotkey mask:
+
+    + Add hotkey mask definitions to ibm.hk
+    + Use the sysfs interface rather than the old procfs interface
+    + Unconditionally try to enable the bits for volume and brightness
+    + Restore the test for the thinkpad key, and start the daemon if
+      setting the corresponding bit doesn't work
+    + For everything else, just accept the driver defaults
+
+  * Thanks to Matthew Garrett for background on the old code and the
+    thinkpad_acpi driver
+
+  * This should address LP: #222796 without reopening LP: #256887
+
+ -- Matt Zimmerman <mdz@ubuntu.com>  Mon, 13 Oct 2008 11:21:30 +0100
+
 hotkey-setup (0.1-23ubuntu5) intrepid; urgency=low
 
   * Add support for Fujitsu siemens Amilo Pa 2548 (LP: #192571)
diff -Nru hotkey-setup-0.1/debian/init.d hotkey-setup-0.1/debian/init.d
--- hotkey-setup-0.1/debian/init.d	2008-09-09 20:49:45.000000000 +0100
+++ hotkey-setup-0.1/debian/init.d	2008-10-13 13:07:09.000000000 +0100
@@ -17,8 +17,9 @@
 
 SAVED_STATE=/var/run/hotkey-setup
 THINKPAD_LOCKFILE=$SAVED_STATE.thinkpad-keys
-THINKPAD_PROC_HOTKEY=/proc/acpi/ibm/hotkey
+THINKPAD_HOTKEY_MASK=/sys/devices/platform/thinkpad_acpi/hotkey_mask
 THINKPAD_KEYS=/usr/sbin/thinkpad-keys
+THINKPAD_HOTKEY_MASK_RECOMMENDED=/sys/devices/platform/thinkpad_acpi/hotkey_recommended_mask
 
 xorg_driver() {
     if [ -e /etc/X11/xorg.conf ] ; then
@@ -60,8 +61,16 @@
     . /usr/share/hotkey-setup/ibm.hk
     modprobe thinkpad-acpi
 
-    # If the top bit (ThinkPad key) sticks, skip the polling-daemon
-    if ! grep -q '0x[8-9a-f].....$' $THINKPAD_PROC_HOTKEY && test -x $THINKPAD_KEYS; then
+	# Unconditionally enable brightness and volume groups
+	# Try to enable ThinkPad key
+	recommended_hotkey_mask=$(cat $THINKPAD_HOTKEY_MASK_RECOMMENDED)
+	wanted_hotkey_mask=$(($recommended_hotkey_mask | $TP_NVRAM_HKEY_GROUP_BRIGHTNESS | $TP_NVRAM_HKEY_GROUP_VOLUME | $TP_ACPI_HKEY_THINKPAD_MASK))
+
+	echo $wanted_hotkey_mask > $THINKPAD_HOTKEY_MASK
+	accepted_hotkey_mask=$(cat $THINKPAD_HOTKEY_MASK)
+
+    # If the ThinkPad key bit was accepted, we don't need the polling daemon
+    if [ $(($accepted_hotkey_mask & $TP_ACPI_HKEY_THINKPAD_MASK)) -eq 0 ] && test -x $THINKPAD_KEYS; then
         if [ ! -c /dev/input/uinput ]; then
             modprobe uinput
         fi
diff -Nru hotkey-setup-0.1/ibm.hk hotkey-setup-0.1/ibm.hk
--- hotkey-setup-0.1/ibm.hk	2008-01-09 22:59:12.000000000 +0000
+++ hotkey-setup-0.1/ibm.hk	2008-10-13 13:04:54.000000000 +0100
@@ -58,3 +58,41 @@
 # Fixed in by removing Pointer_EnableKeys from the default policy in X
 # setkeycodes	45	$KEY_KP6  	# ???
 
+# Derived from Linux drivers/misc/thinkpad_acpi.c mdz@ubuntu.com, 2008-10-13
+TP_ACPI_HOTKEYSCAN_FNF1=0
+TP_ACPI_HOTKEYSCAN_FNF2=1
+TP_ACPI_HOTKEYSCAN_FNF3=2
+TP_ACPI_HOTKEYSCAN_FNF4=3
+TP_ACPI_HOTKEYSCAN_FNF5=4
+TP_ACPI_HOTKEYSCAN_FNF6=5
+TP_ACPI_HOTKEYSCAN_FNF7=6
+TP_ACPI_HOTKEYSCAN_FNF8=7
+TP_ACPI_HOTKEYSCAN_FNF9=8
+TP_ACPI_HOTKEYSCAN_FNF10=9
+TP_ACPI_HOTKEYSCAN_FNF11=10
+TP_ACPI_HOTKEYSCAN_FNF12=11
+TP_ACPI_HOTKEYSCAN_FNBACKSPACE=12
+TP_ACPI_HOTKEYSCAN_FNINSERT=13
+TP_ACPI_HOTKEYSCAN_FNDELETE=14
+TP_ACPI_HOTKEYSCAN_FNHOME=15
+TP_ACPI_HOTKEYSCAN_FNEND=16
+TP_ACPI_HOTKEYSCAN_FNPAGEUP=17
+TP_ACPI_HOTKEYSCAN_FNPAGEDOWN=18
+TP_ACPI_HOTKEYSCAN_FNSPACE=19
+TP_ACPI_HOTKEYSCAN_VOLUMEUP=20
+TP_ACPI_HOTKEYSCAN_VOLUMEDOWN=21
+TP_ACPI_HOTKEYSCAN_MUTE=22
+TP_ACPI_HOTKEYSCAN_THINKPAD=23
+TP_ACPI_HKEY_DISPSWTCH_MASK=$((1 << $TP_ACPI_HOTKEYSCAN_FNF7))
+TP_ACPI_HKEY_DISPXPAND_MASK=$((1 << $TP_ACPI_HOTKEYSCAN_FNF8))
+TP_ACPI_HKEY_HIBERNATE_MASK=$((1 << $TP_ACPI_HOTKEYSCAN_FNF12))
+TP_ACPI_HKEY_BRGHTUP_MASK=$((1 << $TP_ACPI_HOTKEYSCAN_FNHOME))
+TP_ACPI_HKEY_BRGHTDWN_MASK=$((1 << $TP_ACPI_HOTKEYSCAN_FNEND))
+TP_ACPI_HKEY_THNKLGHT_MASK=$((1 << $TP_ACPI_HOTKEYSCAN_FNPAGEUP))
+TP_ACPI_HKEY_ZOOM_MASK=$((1 << $TP_ACPI_HOTKEYSCAN_FNSPACE))
+TP_ACPI_HKEY_VOLUP_MASK=$((1 << $TP_ACPI_HOTKEYSCAN_VOLUMEUP))
+TP_ACPI_HKEY_VOLDWN_MASK=$((1 << $TP_ACPI_HOTKEYSCAN_VOLUMEDOWN))
+TP_ACPI_HKEY_MUTE_MASK=$((1 << $TP_ACPI_HOTKEYSCAN_MUTE))
+TP_ACPI_HKEY_THINKPAD_MASK=$((1 << $TP_ACPI_HOTKEYSCAN_THINKPAD))
+TP_NVRAM_HKEY_GROUP_BRIGHTNESS=$(($TP_ACPI_HKEY_BRGHTUP_MASK|$TP_ACPI_HKEY_BRGHTDWN_MASK))
+TP_NVRAM_HKEY_GROUP_VOLUME=$(($TP_ACPI_HKEY_VOLUP_MASK|TP_ACPI_HKEY_VOLDWN_MASK|TP_ACPI_HKEY_MUTE_MASK))