It looks like suspend to RAM is enabled in the latest PSP kernels (i.e. http://processors.wiki.ti.com/index.php/UserGuidePowerMgmt_PSP_03.00.00.04#Suspend_.26_Resume_2). I tried this out on my OMAP3530 EVM (using a 37xx kernel with mpurate=600 in the bootargs) with both PSP 3.00.00.04 and 3.00.01.06 and it appears to lock up and never come out of the suspension state. On a positive note it seems to go into suspension very quickly:
root@omap3evm:~# echo -n "mem" > /sys/power/state
PM: Syncing filesystems ... done.
Freezing user space processes ... (elapsed 0.01 seconds) done.
Freezing remaining freezable tasks ... (elapsed 0.01 seconds) done.
Suspending console(s) (use no_console_suspend to debug)
Are there any other specific steps to test this capability other than booting the board and running the command shown above than pressing one of the GPIO buttons or a key on the serial terminal?
Ultimately I am looking for the performance of this capability, in particular how long it takes to go in and out of the suspend to RAM state to see if this is feasible for a low power application that needs to wake up periodically to use.
