closing the lid doesn't suspend after upgrading to 15.10

[Adam Funk]

On 2015-12-04, Colin Law wrote:

> On 4 December 2015 at 10:50, Adam Funk <a24061 at ducksburg.com> wrote:
>> Since I upgraded my laptop to 15.10, closing the lid no longer
>> makes it suspend or even lock the screensaver.  When I close the lid,
>> it leaves the stuff below in the syslog.  If I run 'sudo pm-suspend'
>> from xterm or a virtual console, it suspends correctly.  This happens
>> with both the 4.2.0-18 & 4.2.0-19 kernels.  I'd appreciate any
>> suggestions for fixing this.
>
> Do you have an external monitor connected?  If so then that is likely
> the problem.  Ubuntu no longer suspends on lid close with an external
> monitor.  I think that is a bug but others maintain it is a feature.

Is that in the kernel or is it configured somewhere so it's not too
difficult to override?

Alternatively, is there a hook in the lightdm logout that I could use
to run the pm-suspend command automatically after a small delay after
logging out?