[acpid] cannot open input layer

[vitalogy]

Hi,

I installed acpid to use the PowerButton on my CubieTruck to shutdown the device, but that is not working.
The first start of acpid at boot through systemd goes in failure:
# systemctl status acpid
$this->bbcode_second_pass_code('', '
● acpid.service - ACPI event daemon
Loaded: loaded (/usr/lib/systemd/system/acpid.service; enabled; vendor preset: disabled)
Active: active (running) since Di 2015-08-11 00:45:52 CEST; 32s ago
Docs: man:acpid(8)
Main PID: 262 (acpid)
CGroup: /system.slice/acpid.service
└─262 /usr/bin/acpid --foreground --netlink

Aug 11 00:45:52 cubietruck systemd[1]: Started ACPI event daemon.
Aug 11 00:45:52 cubietruck acpid[262]: cannot open input layer
Aug 11 00:45:52 cubietruck acpid[262]: inotify_add_watch() failed: No such file or directory (2)
Aug 11 00:45:52 cubietruck acpid[262]: starting up with netlink and the input layer
Aug 11 00:45:52 cubietruck acpid[262]: 1 rule loaded
Aug 11 00:45:52 cubietruck acpid[262]: waiting for events: event logging is off
Aug 11 00:45:52 cubietruck acpid[262]: RTNETLINK1 answers: No such file or directory
Aug 11 00:45:52 cubietruck acpid[262]: acpid: error talking to the kernel via netlink
')

If acpid is manual restarted all is fine:
# systemctl restart acpid
# systemctl status acpid
$this->bbcode_second_pass_code('', '● acpid.service - ACPI event daemon
Loaded: loaded (/usr/lib/systemd/system/acpid.service; enabled; vendor preset: disabled)
Active: active (running) since Di 2015-08-11 00:56:40 CEST; 1s ago
Docs: man:acpid(8)
Main PID: 570 (acpid)
CGroup: /system.slice/acpid.service
└─570 /usr/bin/acpid --foreground --netlink

Aug 11 00:56:40 cubietruck systemd[1]: Started ACPI event daemon.
Aug 11 00:56:40 cubietruck acpid[570]: starting up with netlink and the input layer
Aug 11 00:56:40 cubietruck acpid[570]: 1 rule loaded
Aug 11 00:56:40 cubietruck acpid[570]: waiting for events: event logging is off
Aug 11 00:56:40 cubietruck acpid[570]: RTNETLINK1 answers: No such file or directory
Aug 11 00:56:40 cubietruck acpid[570]: acpid: error talking to the kernel via netlink
')

After the manual restart of acpid the press on the PowerButton is now recognized:
$this->bbcode_second_pass_code('', 'Aug 11 01:08:37 cubietruck root[583]: PowerButton pressed
Aug 11 01:08:38 cubietruck root[585]: PowerButton pressed
')

I found in this bug report https://bugs.archlinux.org/task/39583 that adding After=systemd-udev-settle.service to the acpid.service should help, but it doesn't for me.
Something goes wrong here, but i don't know how to fix!
Acpid starts propably to early, so the system (input layer) has not finshed yet?
Has someone an idea?

Regards
MichaeL

edit: clarify that acpid fails on boot through systemd