[ltp] Trying to get Suspend to RAM working on an X31

Richard Neill linux-thinkpad@linux-thinkpad.org
Thu, 09 Oct 2014 16:41:20 +0100

On 09/10/14 16:14, John Magolske wrote:
> * Dan Saint-Andre <saint@grillongroup.org> [141004 15:39]:
>> The last time I fought this issue, I learned that suspend-to-RAM
>> [aka, sleep] required a suitable swap space.

I don't think it does. Except when you want to use the added feature of 
"suspend to ram + disk", where it will wake from RAM if it can, but if 
the battery dies, the system will resume from disk. In that case, your 
swap partition must exceed the size of the RAM (and there might be 
issues with encrypted swap).

> In any case, any further clues appreciated!

Can I suggest that you try a selection of distros with live USB keys, 
and see whether any of them work from the USB key?

This is also a very quick way you could try to search through historical 
distros as well as the most modern ones.  My inclination would be to 
scan through a dozen ubuntu live-CDs, (use unetbootin to make the 
environment work off a USB-stick).

Also, I recall 3 possible sources of previous trouble.

1. Sometimes kernel modesetting can be a problem.

2. Double suspend: 2 sets of scripts both race against each other to 
sleep - eg Fn-F4 followed by lid-close. I've noticed some cases when the 

3. A long time ago, I had trouble with X being at fault. The trick  was 
to chvt 1 ; killall -STOP X;   before sleeping, and then the reverse on 
wake.  My A22p (similar hardware) had this issue:

Lastly, I recall that for some generations of thinkpad hardware, in 
about that era, there were two ways to get suspend, one of which used 
APM and the other ACPI. You might wish to try both.  [However, this is a 
distant memory; it may be unreliable!!]

One final thing: it's not always clear whether the X-server and GPU are 
crashed while the kernel is alive. When the machine is non-responsive, 
can you at least ping it? Debugging sleep scripts is much easier over 
SSH (especially if you configure a static IP with wired ethernet: your 
SSH connection should survive a sleep/wake cycle if it is quick enough).



> John