[linux-pm] ARM hibernation / suspend-to-disk

[Sebastian Capella]

Quoting TonyHo (2014-03-04 03:04:08)
> Hi Sebastian:
>      Thank you. And I'm in Shanghai, it's not far from the Macao, both 
> in China, ha.
> The system can boot up normal now. And I want to make the hibernation, 
> but error occurs. I want to save the hibernation image in 
> /dev/mmcblk0p3(device id 179:3), and I configure this in menuconfig:
> / # cat /sys/power/resume 179:3
> When I echo a disk to /sys/power/state , it hints(partly log):
> [ 49.426656] omap_uart 44e09000.serial: no wakeirq for uart0
> [ 49.594385] PM: thaw of devices complete after 171.291 msecs
> [ 49.661876] PM: Cannot find swap device, try swapon -a.
> [ 49.667356] PM: Cannot get swap writer
> [ 49.722677] Restarting tasks ... done. ash: write error: No such device
> 
> But I can find my device /dev/mmcblk0p3, and its size is about 2GB, and 
> it's not mounted in system,it can be mounted with ext4 filesystem.
> / # ls -l /dev/mmcblk*
> brw-rw---- 1 0 0 179, 3 Jan 1 00:01 /dev/mmcblk0p3
> 
> It says cannot find swap device, but the CONFIG_SWAP=y is checked.
> It seems I miss something?

Hi tony,
          
Two things are missing:

1) you must format the partition as swap using the mkswap command.  This can be
   done on target or on your laptop.  

2) after booting, on target you have to add the swap to the system using the
   swapon command.  I usually do:

    swapon /dev/mmcblk0p3

If you want to do swapon -a you may have to modify the
/etc/fstab or mnttab but I don't do it this way.  

Sebastian