我正在使用 Ubuntu 14.04.2 LTS，内核为 3.16.0-38-generic #52~14.04.1-Ubuntu SMP Fri May 8 09:43:57 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux。
电脑型号：iMac Late 2009（https://support.apple.com/kb/SP696?locale=en_US）
我的电脑是基于 EFI 的（不是 BIOS）。而且我没有在 grub 配置文件中看到“noapic、nolapic”设置。
我有一个 Intel(R) Core(TM)2 Duo CPU，但有时当我启动系统时只能检测到 1 个 CPU 核心。
这是仅检测到核心时的 dmesg 输出：
[ 0.000000] smpboot: Allowing 2 CPUs, 0 hotplug CPUs
[ 0.073437] smpboot: CPU0: Intel(R) Core(TM)2 Duo CPU E7600 @ 3.06GHz (fam: 06, model: 17, stepping: 0a)
[ 5.088430] smpboot: CPU1: Not responding
[ 5.088440] smpboot: do_boot_cpu failed(1) to wakeup CPU#1
[ 5.088448] smpboot: Total of 1 processors activated (6102.83 BogoMIPS)
[ 0.076000] Kernel panic - not syncing: smp_callin: CPU1 started up but did not get a callout!
[ 0.076000] ---[ end Kernel panic - not syncing: smp_callin: CPU1 started up but did not get a callout!
这是检测到所有核心时的 dmesg 输出：
[ 0.000000] smpboot: Allowing 2 CPUs, 0 hotplug CPUs
[ 0.073319] smpboot: CPU0: Intel(R) Core(TM)2 Duo CPU E7600 @ 3.06GHz (fam: 06, model: 17, stepping: 0a)
[ 0.086922] smpboot: Total of 2 processors activated (12206.00 BogoMIPS)
USB 设备：
$ lsusb
Bus 002 Device 004: ID 05ac:8403 Apple, Inc. Internal Memory Card Reader
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 003: ID 045e:078c Microsoft Corp.
Bus 004 Device 004: ID 05ac:8215 Apple, Inc. Built-in Bluetooth 2.0+EDR HCI
Bus 004 Device 002: ID 0a5c:4500 Broadcom Corp. BCM2046B1 USB 2.0 Hub (part of BCM2046 Bluetooth)
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 003: ID 05ac:8502 Apple, Inc. Built-in iSight
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 003 Device 003: ID 05ac:8242 Apple, Inc. Built-in IR Receiver
Bus 003 Device 002: ID 045e:0040 Microsoft Corp. Wheel Mouse Optical
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
我只插了微软旧键盘和鼠标（使用了 4 个 USB 端口中的 2 个）。
我该怎么做才能解决这个问题？
谢谢。