Comment # 1 on bug 1058814 from Hendrik Woltersdorf

After more tests and check I found, that the backlight helper process
(systemd-backlight@backlight:fujitsu-laptop.service) fails and this seems to
prevent "suspend to [disk|ram]" from working:


Sep 16 14:37:21 schlepptop.site systemd-logind[1342]: Delay lock is active (UID
0/root, PID 2055/upowerd) but inhibitor timeout is reached.
Sep 16 14:37:21 schlepptop.site systemd[1]: Reached target Sleep.
Sep 16 14:37:21 schlepptop.site systemd[1]: Starting Hibernate...
Sep 16 14:37:21 schlepptop.site kernel: PM: Hibernation mode set to 'platform'
Sep 16 14:37:21 schlepptop.site systemd-sleep[3644]: INFO: running
/usr/lib/systemd/system-sleep/grub2.sleep for hibernate
Sep 16 14:37:21 schlepptop.site systemd-sleep[3644]: INFO: Running prepare-grub
..
Sep 16 14:37:22 schlepptop.site systemd-sleep[3644]:   running kernel is grub
menu entry openSUSE Tumbleweed (vmlinuz-4.13.1-1-pae)
Sep 16 14:37:22 schlepptop.site systemd-sleep[3644]:   preparing boot-loader:
selecting entry openSUSE Tumbleweed, kernel /boot/4.13.1-1-pae
Sep 16 14:37:23 schlepptop.site systemd-sleep[3644]:   running
/usr/sbin/grub2-once "openSUSE Tumbleweed"
Sep 16 14:37:24 schlepptop.site systemd-sleep[3644]:     time needed for sync:
0.8 seconds, time needed for grub: 0.8 seconds.
Sep 16 14:37:24 schlepptop.site systemd-sleep[3644]: INFO: Done.
Sep 16 14:37:24 schlepptop.site kernel: PM: Syncing filesystems ... 
Sep 16 14:37:24 schlepptop.site systemd-sleep[3644]: Suspending system...
Sep 16 14:37:44 schlepptop.site kernel: PM: done.
Sep 16 14:37:44 schlepptop.site kernel: Freezing user space processes ... 
Sep 16 14:37:44 schlepptop.site kernel: Freezing of tasks failed after 20.006
seconds (1 tasks refusing to freeze, wq_busy=0):
Sep 16 14:37:44 schlepptop.site kernel: systemd-backlig D    0  3047      1
0x00000004
Sep 16 14:37:44 schlepptop.site kernel: Call Trace:
Sep 16 14:37:44 schlepptop.site kernel:  ? __schedule+0x298/0x910
Sep 16 14:37:44 schlepptop.site kernel:  ? schedule+0x35/0x80
Sep 16 14:37:44 schlepptop.site kernel:  ? schedule_preempt_disabled+0x14/0x20
Sep 16 14:37:44 schlepptop.site kernel:  ? __mutex_lock.isra.1+0x20c/0x4b0
Sep 16 14:37:44 schlepptop.site kernel:  ?
backlight_device_set_brightness+0x1c/0xb0
Sep 16 14:37:44 schlepptop.site kernel:  ? brightness_store+0x29/0x40
Sep 16 14:37:44 schlepptop.site kernel:  ?
backlight_device_set_brightness+0xb0/0xb0
Sep 16 14:37:44 schlepptop.site kernel:  ? dev_attr_store+0x18/0x30
Sep 16 14:37:44 schlepptop.site kernel:  ? sysfs_kf_write+0x2e/0x50
Sep 16 14:37:44 schlepptop.site kernel:  ? sysfs_kf_bin_read+0xc0/0xc0
Sep 16 14:37:44 schlepptop.site kernel:  ? kernfs_fop_write+0xea/0x170
Sep 16 14:37:44 schlepptop.site kernel:  ? kernfs_vma_page_mkwrite+0x70/0x70
Sep 16 14:37:44 schlepptop.site kernel:  ? __vfs_write+0x22/0x150
Sep 16 14:37:44 schlepptop.site kernel:  ? common_file_perm+0x4d/0x120
Sep 16 14:37:44 schlepptop.site kernel:  ? __alloc_fd+0x9d/0x160
Sep 16 14:37:44 schlepptop.site kernel:  ? security_file_permission+0x31/0xb0
Sep 16 14:37:44 schlepptop.site kernel:  ? vfs_write+0x94/0x1a0
Sep 16 14:37:44 schlepptop.site kernel:  ? SyS_write+0x3c/0x90
Sep 16 14:37:44 schlepptop.site kernel:  ? do_fast_syscall_32+0x71/0x150
Sep 16 14:37:44 schlepptop.site kernel:  ? entry_SYSENTER_32+0x4e/0x7c
Sep 16 14:37:44 schlepptop.site kernel: OOM killer enabled.
Sep 16 14:37:44 schlepptop.site rtkit-daemon[2249]: The canary thread is
apparently starving. Taking action.
Sep 16 14:37:44 schlepptop.site rtkit-daemon[2249]: Demoting known real-time
threads.
Sep 16 14:37:44 schlepptop.site rtkit-daemon[2249]: Successfully demoted thread
2287 of process 2245 (/usr/bin/pulseaudio).
Sep 16 14:37:44 schlepptop.site rtkit-daemon[2249]: Successfully demoted thread
2286 of process 2245 (/usr/bin/pulseaudio).
Sep 16 14:37:44 schlepptop.site rtkit-daemon[2249]: Successfully demoted thread
2245 of process 2245 (/usr/bin/pulseaudio).
Sep 16 14:37:44 schlepptop.site rtkit-daemon[2249]: Demoted 3 threads.
Sep 16 14:37:44 schlepptop.site kernel: Restarting tasks ... done.
Sep 16 14:37:44 schlepptop.site systemd[1]: systemd-hibernate.service: Main
process exited, code=exited, status=1/FAILURE
Sep 16 14:37:44 schlepptop.site systemd[1]: Failed to start Hibernate.
Sep 16 14:37:44 schlepptop.site systemd[1]: Dependency failed for Hibernate.
Sep 16 14:37:44 schlepptop.site systemd-logind[1342]: Operation 'sleep'
finished.
Sep 16 14:37:44 schlepptop.site systemd[1]: hibernate.target: Job
hibernate.target/start failed with result 'dependency'.
Sep 16 14:37:44 schlepptop.site systemd[1]: sleep.target: Unit not needed
anymore. Stopping.
Sep 16 14:37:44 schlepptop.site systemd[1]: systemd-hibernate.service: Unit
entered failed state.
Sep 16 14:37:44 schlepptop.site systemd[1]: systemd-hibernate.service: Failed
with result 'exit-code'.
Sep 16 14:37:44 schlepptop.site systemd[1]: Stopped target Sleep.