Had issues after upgrading to Karmic with suspend/resume on my media box (Shuttle SN78S) where the system would suspend and then immediately resume (xbmc forum thread). After ruling out the nvidia blob as the culprit (my usual suspect), I did a bit more digging and found people able to make it work by disabling usb autosuspend but that didn’t make a difference at all for me. I did find some older documentation pointing to an oddity with the ehci driver and acpi wakeup causing this issue so I disabled it (via /proc/acpi/wakeup) and was able to suspend successfully. Wakeup via WOL succeeded as well, but not being able to resume via remote is a showstopper for me so I poked a bit more and enabled wakeup only for the USB device my remote sensor was attached to and voila!

To determine the USB device:

root@host:~#lsusb
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 002: ID 1784:0008 TopSeed Technology Corp.
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

In this case it’s easy as my remote sensor is the only device attached and it’s on bus 004.


root@host:~#cat /proc/acpi/wakeup |grep ^USB
USB0 S3 disabled pci:0000:00:02.0
USB1 S3 enabled pci:0000:00:04.0
USBB S3 disabled pci:0000:00:04.1
USB2 S3 disabled pci:0000:00:02.1

Now I have both the USB1 and USBB devices that show up on 04, but USB1 is the first so that was the one I enabled via:
echo "USB1" > /proc/acpi/wakeup

To make it persistent I added the following to /etc/rc.local (the ethtool command enables WOL and isn’t needed unless you want to wake your machine over the network):

# Enable wakeup for the remote
status=`cat /proc/acpi/wakeup | grep "USB1" | awk {'print $3}'`
if [ "$status" = "disabled" ]; then
echo "USB1" > /proc/acpi/wakeup
fi

/usr/sbin/ethtool -s eth0 wol g > /dev/null


The only other step I took was to work around the standard lirc borkage by disabling lirc and unloading the modules. This requires two files:
/etc/pm/config.d/01lirc_module

SUSPEND_MODULES="lirc_mceusb lirc_dev"


/etc/pm/sleep.d/10-lirc (must be executable, requires installing curl – apt-get install curl)

#!/bin/sh
# Disconnect XBMC from lirc and stop the daemon

case "$1" in
hibernate|suspend)
service lirc stop
;;
thaw|resume)
service lirc start
;;
*) exit $NA
;;
esac


As of 9.11 alpha 2, XBMC uses ConsoleKit in the Karmic packages so you need to make sure your session gets auth’d properly or you’ll end up with permission denied messages in the xbmc logs when it tries to suspend. If you’re using GDM or KDM it should Just Work. In my case I’m just starting x on tty1 for my xbmc user so I had to update my .xsession file to launch xbmc like so:
ck-launch-session /usr/bin/xbmc --standalone

Edit: As of 9.11 alpha2, XBMC takes care of connecting/disconnecting from the LIRC daemon so no need to do it in the lirc script. Also added info about the new ConsoleKit integration in alpha2.
Edit2: Maverick requires a few other tweaks to work properly, updates are here.