Arch Linux

Description:
After the most recent kernel26 and linux-firmware update (versions below) I am unable to suspend to RAM. The problem manifests itself as a failed write to /sys/power/state

Here are the permissions on the file:
# ls -l /sys/power/state
-rw-r--r-- 1 root root 4096 May 14 13:30 /sys/power/state

It appears to be root writable, but I get this error in /var/log/pm-suspend.log:
Sat May 14 13:28:44 MDT 2011: performing suspend
/usr/lib/pm-utils/pm-functions: line 297: echo: write error: No such file or directory
Sat May 14 13:28:55 MDT 2011: Awake.

For reference, the line in /usr/lib/pm-utils/pm-functions that is erroring does this:
do_suspend() { echo -n "mem" >/sys/power/state; }

When I manually run 'echo -n "mem" >/sys/power/state' the laptop starts to suspend and then wakes up again almost immediately. Here's the output (as root):
# echo -n "mem" > /sys/power/state
-bash: echo: write error: No such file or directory

It's probably related to these errors that appear in dmesg near each suspend attempt:
[ 7681.827779] PM: Preparing system for mem sleep
[ 7682.300749] dell-wmi: Received unknown WMI event (0x11)
[ 7682.779373] Freezing user space processes ...
[ 7682.785835] dell-wmi: Received unknown WMI event (0x11)
[ 7682.792384] (elapsed 0.01 seconds) done.
[ 7682.792387] Freezing remaining freezable tasks ... (elapsed 0.01 seconds) done.
[ 7682.805665] PM: Entering mem sleep
[ 7682.805771] Suspending console(s) (use no_console_suspend to debug)
[ 7682.829157] sd 0:0:0:0: [sda] Synchronizing SCSI cache
[ 7682.829439] sd 0:0:0:0: [sda] Stopping disk
[ 7682.844754] pci 0000:00:1f.3: PCI INT C disabled
[ 7682.844838] ACPI handle has no context!
[ 7682.844890] HDA Intel 0000:00:1b.0: PCI INT A disabled
[ 7682.844905] sdhci-pci 0000:03:00.0: PCI INT B disabled
[ 7682.868864] ehci_hcd 0000:00:1d.0: PCI INT A disabled
[ 7682.925291] ehci_hcd 0000:00:1a.0: PCI INT A disabled
[ 7686.923261] e1000e 0000:00:19.0: eth0: Could not read PHY page 769
[ 7686.923278] pci_pm_suspend(): e1000_suspend+0x0/0x40 [e1000e] returns -2
[ 7686.923283] pm_op(): pci_pm_suspend+0x0/0x130 returns -2
[ 7686.923286] PM: Device 0000:00:19.0 failed to suspend async: error -2
[ 7686.923375] PM: Some devices failed to suspend

Additional info:
* package version(s)
kernel26 2.6.38.6-2
linux-firmware 20110512-2
pm-quirks 0.20100619-1
pm-utils 1.4.1-3