[systemd-devel] Suspend from wireless keyboard not working

[Jan Alexander Steffens]

On Sat, Feb 14, 2015 at 5:34 AM, Gustavo De Nardin (spuk)
<gustavodn at gmail.com> wrote:
> Excuse the ignorance, but why is it a problem if every keyboard would get
> the 'power-switch' tag (or if it wouldn't be needed)? For example, would it
> be a problem if a distro adds the power-switch tag to all keyboards by
> default? If the kernel is in a sleep state, how would it matter to filter
> such events? Or is the idea for it to be able to filter such events
> immediately after being awoken and then get back to the sleep state?

Not "wakeup" from the system sleeping, but the logind process
sleeping. To react to power key presses, logind has to process every
keypress and filter for the right keys itself. This is why it only
listens to special "keyboards" with a limited number of keys. If it
would listen to all keyboards, the logind process would have to do
work on every keypress from the user, even though if only cares about
a vanishingly small fraction of them. Lennart would like the kernel to
do the filtering before sending the presses to logind to avoid the
overhead.