我有一台新的 Dell Latitude E7440，装有 Ubuntu 14.04.2。有时（但并非总是）睡眠后我无法恢复，因为尝试恢复后会发生以下情况之一：
- 我可以移动鼠标，但无法控制键盘并输入密码（并且鼠标光标保持箭头形状）
- 我甚至无法移动鼠标
- 我看到黑屏
当我尝试唤醒计算机时，内核日志显示了一些错误：
Apr 8 09:10:18 lati kernel: [22586.645486] ACPI Error: Index value 0x0000000000000083 overflows field width 0x7 (20140424/exfldio-343)
Apr 8 09:10:18 lati kernel: [22586.645489] ACPI Error: Method parse/execution failed [\NEVT] (Node ffff88040e047258), AE_AML_REGISTER_LIMIT (20140424/psparse-536)
Apr 8 09:10:18 lati kernel: [22586.645491] ACPI Error: Method parse/execution failed [\_SB_.PCI0.LPCB.ECDV._Q66] (Node ffff88040e044b90), AE_AML_REGISTER_LIMIT (20140424/psparse-536)
这些错误消息之后出现一个警告：
Apr 8 09:10:18 lati kernel: [22638.968661] WARNING: CPU: 0 PID: 27214 at /build/buildd/linux-lts-utopic-3.16.0/drivers/gpu/drm/i915/intel_display.c:3324 intel_crtc_wait_for_pending_flips+0x171/0x180 [i915]()
睡觉前的最后一条信息是：
Apr 7 23:42:34 lati kernel: [22578.986188] PM: Preparing system for mem sleep
您认为内核日志是否提示了我的笔记本电脑的睡眠问题？
更新
尝试“睡眠”并再次唤醒后，问题依然存在（可以移动鼠标，但无法点击或输入任何内容），但这次日志消息有所不同。以下是其中一小部分。
睡前最后一条留言：
Apr 8 11:44:08 lati kernel: [ 4736.851598] ahci 0000:00:1f.2: port does not support device sleep
在那之后的一行，出现了这行最奇怪的行（在 vim 中；可能表示文件损坏或出现其他问题..？）
^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@Apr 8 13:52:03 lati kernel: [ 0.000000] Initializing cgroup subsys cpuset
（实际的队伍要长得多……）
稍后出现以下警告：
Apr 8 13:52:03 lati kernel: [ 0.910836] i8042: Warning: Keylock active
系统日志非常相似。休眠前的最后两行如下所示：
Apr 8 11:44:08 lati kernel: [ 4736.851598] ahci 0000:00:1f.2: port does not support device sleep
Apr 8 11:44:08 lati kernel: [ 4737.399980] init: anacron main process (3054) killed by TERM signal
然后再看这一^@行，最后是那些错误和警告：
Apr 8 13:52:03 lati kernel: [ 0.910836] i8042: Warning: Keylock active
Apr 8 13:52:03 lati kernel: [ 2.724522] systemd-udevd[352]: Error calling EVIOCSKEYCODE: Invalid argument
Apr 8 13:52:03 lati NetworkManager[727]: <warn> failed to allocate link cache: (-12) Object not found
Apr 8 13:52:03 lati NetworkManager[727]: <warn> /sys/devices/virtual/net/lo: couldn't determine device driver; ignoring...
Apr 8 13:52:03 lati NetworkManager[727]: <warn> Trying to remove a non-existant call id.
Apr 8 13:52:05 lati ModemManager[697]: <warn> Couldn't find support for device at '/sys/devices/pci0000:00/0000:00:19.0': not supported by any plugin
Apr 8 13:52:05 lati ModemManager[697]: <warn> Couldn't find support for device at '/sys/devices/pci0000:00/0000:00:1c.3/0000:02:00.0': not supported by any plugin
Apr 8 13:52:08 lati NetworkManager[727]: <warn> dnsmasq not available on the bus, can't update servers.
Apr 8 13:52:08 lati NetworkManager[727]: <error> [1428490328.454641] [nm-dns-dnsmasq.c:396] update(): dnsmasq owner not found on bus: Could not get owner of name 'org.freedesktop.NetworkManager.dnsmasq': no such name
Apr 8 13:52:08 lati NetworkManager[727]: <warn> DNS: plugin dnsmasq update failed
Apr 8 13:52:08 lati dnsmasq[1666]: warning: no upstream servers configured
Apr 8 13:52:08 lati NetworkManager[727]: <warn> dnsmasq appeared on DBus: :1.47
Apr 8 13:52:20 lati ModemManager[697]: <warn> Could not grab port (tty/ttyS4): 'Cannot add port 'tty/ttyS4', unhandled serial type'
Apr 8 13:52:20 lati ModemManager[697]: <warn> Couldn't create modem for device at '/sys/devices/pci0000:00/0000:00:16.3': Failed to find primary AT port
Apr 8 13:52:47 lati gnome-session[2016]: GLib-CRITICAL: g_environ_setenv: assertion 'value != NULL' failed