在我的系统上，colord-sane可重复阻止系统挂起到 RAM。
这是我在系统日志中找到的内容：
systemd-sleep[32375]: Suspending system...
kernel: [55908.804118] PM: suspend entry (deep)
kernel: [55908.804123] PM: Syncing filesystems ... done.
kernel: [55908.816176] Freezing user space processes ...
kernel: [55928.828200] Freezing of tasks failed after 20.012 seconds (2 tasks refusing to freeze, wq_busy=0):
kernel: [55928.828567] colord-sane D 0 32106 1 0x00000004
kernel: [55928.828577] Call Trace:
我尝试过sudo kill -9 colord-sane，但是没有用，进程就是不消失。sudo service colord stop也没有什么帮助，它只是在系统日志中生成了这些：
systemd[1]: colord.service: State 'stop-sigterm' timed out. Killing.
systemd[1]: colord.service: Processes still around after SIGKILL. Ignoring.
systemd[1]: colord.service: State 'stop-final-sigterm' timed out. Killing.
systemd[1]: colord.service: Processes still around after final SIGKILL. Entering failed mode.
systemd[1]: colord.service: Unit entered failed state.
systemd[1]: colord.service: Failed with result 'timeout'.
但即使服务处于“失败”状态，该colord-sane过程仍然存在。
我该如何终止colord-sane以便我的系统可以再次进入睡眠状态？
（这是基于 Ubuntu 16.04 LTS 的 KDE neon 5.13。）