While trying to enter sleep mode on beaglebone black am getting an error
When i issue the command echo -n "mem" > /sys/power/state am getting
-sh: echo: write error: No such device
The kernel version and os version is as below
root@beaglebone:~# uname -a
Linux beaglebone 3.8.13 #1 SMP Wed Sep 4 09:09:32 CEST 2013 armv7l GNU/Linux
root@beaglebone:~# lsb_release -a
Distributor ID: Angstrom
Description: Angstrom GNU/Linux v2012.12 (Core edition)
Release: v2012.12
Codename: Core edition
I was just trying to do the same thing and got the same error. Looks like the 3.8.13 kernel doesn't support suspend/sleep mode. In the link below they mention only 3.12 or higher supports that feature. (Note if you upgrade beyond 3.8.13 all the capemgr stuff works completely differently than on 3.8.13. I tried 3.18.1 and couldn't get any capes to work.)
Bug report for sleep mode