[systemd-devel] suspend-utils and systemd

[Peter Dahlberg]

Hi,

> We only support the in-kernel default suspend-to-disk and suspend-to-ram
> implementations. We don't really support any other implementations of
> the logic upstream, and especially not out-of-tree ones.
> 
> You can of course override the implementation of systemd-suspend.service
> and system-hibernate.service, to whatever you like.
> 
> However, I really wonder, what's wrong with the normal in-kernel
> implementations? Why use something else?

The kernel provides an interface to let a userspace utility handle the memory 
snapshot instead of reading/writing it from/to disk itself [1] with suspend-
utils/uswsusp [2] as the reference implementation. The most notable Features 
are (which as far as i know are not supported by the in-kernel 
implementation):

- suspend image checksumming
- suspend image compression
- suspend image encryption 
- (limited) support for splash screens and graphical progress meters

[1] https://www.kernel.org/doc/Documentation/power/userland-swsusp.txt
[2] http://suspend.sourceforge.net/