[systemd-devel] Having systemd shutdown when pressing the power button

[Koen Kooi]

Op 28 aug. 2014, om 15:42 heeft Lennart Poettering <lennart at poettering.net> het volgende geschreven:

> On Thu, 28.08.14 10:50, Koen Kooi (koen at dominion.thruhere.net) wrote:
> 
>> Hi,
> 
> Heya,
> 
>> I am working on a system (http://www.acmesystems.it/arietta) where I
>> hooked up the button as a power key:
>> 
>> 	https://github.com/koenkooi/linux/commit/c823e0b046efcfff61e21fa4c89d5d68090ef6de
>> 
>> Evtest shows it doing the right thing (issuing KEY_POWER) when being
>> pressed, but systemd seems to totally ignore it. I've seen this
>> behaviour in the past and noticed the DE (GNOME2, old but it works)
>> would pick it up and present the dialog. Since this is a headless
>> system I want systemd to handle it instead of the DE (which isn't
>> installed).  Every doc or blog post I read says that systemd should
>> already be handling it, but it isn't in my case. I suspect that
>> systemd only handles ACPI powerkey events, but I haven't actually
>> looked at the code.
>> 
>> Are more people experiencing this and does someone have a workaround
>> or fix?
> 
> You have to tag your input devices with the "power-switch" udev tag,
> otherwise logind won't pick up the device.
> 
> See 70-power-switch.rules for the current default:
> 
>        SUBSYSTEM=="input", KERNEL=="event*", SUBSYSTEMS=="acpi", TAG+="power-switch"
>        SUBSYSTEM=="input", KERNEL=="event*", KERNELS=="thinkpad_acpi", TAG+="power-switch"

Thanks, I've sent 2 patches to add rules for more power buttons, but...

> 
> I'd really like to open this up, to be done on all kbds by default, but
> I feel uneasy about listening to all keypresses on all keyboards by
> default.... We don't want that logind is woken up on virtually *all*
> keypresses on the entire system, all the time.

... patch 2/2 opens up gpio-keys for this. All the boards I have in my office use gpio-keys for things like up/down, volume or other 'control' type of things. Matrix setups use a different driver, so I don't expect this to catch proper keyboards. Having said that, I can understand if you reject 2/2.

regards,

Koen

> 
> David Hermann did a kernel patch to improve the situation:
> 
> https://www.mail-archive.com/linux-input@vger.kernel.org/msg11143.html
> 
> With this in place, userspace can set a mask of input keys it is
> interested in, and we could use that for logind to just subscribe to
> power keypresses and be happy...
> 
> Unfortunately though the patch got repeatedly ignored by the input
> maintainers, even though it got resent multiple times... :-(
> 
> Lennart
> 
> -- 
> Lennart Poettering, Red Hat