# Spontaneous wake ups from suspend


When I upgraded my Ubuntu 14.04 to use kernel 4.0 (and now kernel 4.1) it apparently
got a new feature: it would wake up from suspend in the middle of the day...

This [bug](https://bugs.launchpad.net/dell-sputnik/+bug/1161962) provides a good read
and has pointers to articles with more background. I'm seeing this on my [Macbook
Air](http://miek.nl/posts/2013/Aug/31/macbook-air-61-2013-model-with-ubuntu/)
and I am still not sure what the root cause is. I'm also not sure if it *is*
"Intel Rapid Start Technology", as Apples don't have a BIOS to speak off.

What *does* seem to help is setting which thing (bus, controller, lid) can wakeup the
computer. The file that controls this is `/proc/acpi/wakeup` (showing small snippet):

    Device  S-state   Status   Sysfs node
    XHC1      S3    *disabled  pci:0000:00:14.0
    LID0      S4    *enabled   platform:PNP0C0D:00

Now, echo-ing `LID0` to the file toggles that state, from `enabled` to `disabled`. For `LID0`
you probable want to keep it *enabled*. In my case I has to disable `XHC1` for this to work -
however I am still testing if this actually fixes things. Looking good though with the 4.1 kernel.

## Update (28 June)

Hmmm. I now see the opposite problem: laptop refused to suspend. A normal suspend looks
like this:

    % sudo acpi_listen
    [sudo] password for miek:
    button/lid LID close
    button/lid LID open

But after a few cycles (or a long sleep?), `acpi_listen` does not see any events anymore...

## Update (29 June)

...And back to the kernel from Ubuntu 14.04 (3.13).