我现在正为此而抓狂：我的电脑经常和反复自升级到 14.04LTS 后无法启动，顺序如下：
- 打开
- 邮政
- GRUB 启动
- Grub 倒计时，调用 Ubuntu
- 空白屏幕，然后加载文本、内容等......
- 然后就黑了，死机了。显示器因没有视频信号而断电。
键盘和鼠标也坏了，没有数字锁定灯，鼠标传感器没有光，大写锁定键没有任何反应（大写锁定灯不切换）。
我必须强制关闭电脑电源才能重新启动。尝试几次后，电脑可能最终会完全启动。
当它最终启动时，我没有收到任何错误消息。
我不想在这篇文章中到处散布随机日志文件和调试等内容，所以请询问我能提供的任何信息，我会将其粘贴进去。同样，任何要运行的命令/要尝试的实验我都会尝试并报告。
系统是相当普通的单启动 PC：双 Xeon X5660 64 位 / 48G RAM / 256G SSD 启动驱动器 / 4TB 硬盘（用于我的垃圾）/ ATI 3650 显卡 / 双 DVI 显示器。除了 LAN 电缆外，没有插入任何其他设备。
即使是模糊的提示，比如在哪里查看、日志文件要挖掘等，也会受到欢迎——我对命令行和其他东西相当熟悉，只是不熟悉足够的了解 Ubuntu 的内部工作原理，知道从哪里开始！
编辑：终于从日志中裁剪出一些东西了！
日志中大部分内容如下：
Dec 18 23:01:27 Puter kernel: [ 8571.122775] [drm:drm_mode_addfb], [FB:51]
Dec 18 23:01:27 Puter kernel: [ 8571.122781] [drm:radeon_crtc_page_flip], flip-ioctl() cur_fbo = ffff8805fe615400, cur_bbo = ffff880bff782800
Dec 18 23:01:27 Puter kernel: [ 8571.122794] [drm:radeon_crtc_page_flip], flip-ioctl() cur_fbo = ffff8805fe615400, cur_bbo = ffff880bff782800
Dec 18 23:01:27 Puter kernel: [ 8571.667217] [drm:drm_mode_addfb], [FB:50]
Dec 18 23:01:27 Puter kernel: [ 8571.667224] [drm:radeon_crtc_page_flip], flip-ioctl() cur_fbo = ffff880bff782800, cur_bbo = ffff8805fe615400
Dec 18 23:01:27 Puter kernel: [ 8571.667236] [drm:radeon_crtc_page_flip], flip-ioctl() cur_fbo = ffff880bff782800, cur_bbo = ffff8805fe615400
Dec 18 23:01:28 Puter kernel: [ 8572.488325] [drm:drm_mode_addfb], [FB:51]
Dec 18 23:01:28 Puter kernel: [ 8572.488332] [drm:radeon_crtc_page_flip], flip-ioctl() cur_fbo = ffff8805fe615400, cur_bbo = ffff880bff782800
Dec 18 23:01:28 Puter kernel: [ 8572.488344] [drm:radeon_crtc_page_flip], flip-ioctl() cur_fbo = ffff8805fe615400, cur_bbo = ffff880bff782800
但无论在顺境还是逆境，这都是一样的，我在谷歌上搜索过，似乎没有人真正关心。但是，实际上有大约 200Mb 的内容不停地发送到 kern.log 中。
这是显示上次（重新）启动的日志，不幸的是我看不到任何确凿的证据：
Dec 18 23:01:26 Puter kernel: [ 8570.170086] [drm:drm_mode_addfb], [FB:51]
Dec 18 23:01:26 Puter kernel: [ 8570.170093] [drm:radeon_crtc_page_flip], flip-ioctl() cur_fbo = ffff8805fe615400, cur_bbo = ffff880bff782800
Dec 18 23:01:26 Puter kernel: [ 8570.170105] [drm:radeon_crtc_page_flip], flip-ioctl() cur_fbo = ffff8805fe615400, cur_bbo = ffff880bff782800
Dec 18 23:01:26 Puter kernel: [ 8570.187846] [drm:drm_mode_addfb], [FB:50]
Dec 18 23:01:26 Puter kernel: [ 8570.187853] [drm:radeon_crtc_page_flip], flip-ioctl() cur_fbo = ffff880bff782800, cur_bbo = ffff8805fe615400
Dec 18 23:01:26 Puter kernel: [ 8570.187865] [drm:radeon_crtc_page_flip], flip-ioctl() cur_fbo = ffff880bff782800, cur_bbo = ffff8805fe615400
Dec 18 23:01:26 Puter kernel: [ 8570.217859] [drm:drm_mode_addfb], [FB:51]
Dec 18 23:01:26 Puter kernel: [ 8570.217866] [drm:radeon_crtc_page_flip], flip-ioctl() cur_fbo = ffff8805fe615400, cur_bbo = ffff880bff782800
Dec 18 23:01:26 Puter kernel: [ 8570.217878] [drm:radeon_crtc_page_flip], flip-ioctl() cur_fbo = ffff8805fe615400, cur_bbo = ffff880bff782800
Dec 18 23:01:26 Puter kernel: [ 8570.242266] [drm:drm_mode_addfb], [FB:50]
Dec 18 23:01:26 Puter kernel: [ 8570.242273] [drm:radeon_crtc_page_flip], flip-ioctl() cur_fbo = ffff880bff782800, cur_bbo = ffff8805fe615400
Dec 18 23:01:26 Puter kernel: [ 8570.242286] [drm:radeon_crtc_page_flip], flip-ioctl() cur_fbo = ffff880bff782800, cur_bbo = ffff8805fe615400
Dec 18 23:01:26 Puter kernel: [ 8570.466341] [drm:drm_mode_addfb], [FB:51]
Dec 18 23:01:26 Puter kernel: [ 8570.466348] [drm:radeon_crtc_page_flip], flip-ioctl() cur_fbo = ffff8805fe615400, cur_bbo = ffff880bff782800
Dec 18 23:01:26 Puter kernel: [ 8570.466360] [drm:radeon_crtc_page_flip], flip-ioctl() cur_fbo = ffff8805fe615400, cur_bbo = ffff880bff782800
Dec 18 23:01:26 Puter kernel: [ 8570.506137] [drm:drm_mode_addfb], [FB:50]
Dec 18 23:01:26 Puter kernel: [ 8570.506143] [drm:radeon_crtc_page_flip], flip-ioctl() cur_fbo = ffff880bff782800, cur_bbo = ffff8805fe615400
Dec 18 23:01:26 Puter kernel: [ 8570.506156] [drm:radeon_crtc_page_flip], flip-ioctl() cur_fbo = ffff880bff782800, cur_bbo = ffff8805fe615400
Dec 18 23:01:26 Puter kernel: [ 8570.754652] [drm:drm_mode_addfb], [FB:51]
Dec 18 23:01:26 Puter kernel: [ 8570.754659] [drm:radeon_crtc_page_flip], flip-ioctl() cur_fbo = ffff8805fe615400, cur_bbo = ffff880bff782800
Dec 18 23:01:26 Puter kernel: [ 8570.754671] [drm:radeon_crtc_page_flip], flip-ioctl() cur_fbo = ffff8805fe615400, cur_bbo = ffff880bff782800
Dec 18 23:01:26 Puter kernel: [ 8570.786391] [drm:drm_mode_addfb], [FB:50]
Dec 18 23:01:26 Puter kernel: [ 8570.786398] [drm:radeon_crtc_page_flip], flip-ioctl() cur_fbo = ffff880bff782800, cur_bbo = ffff8805fe615400
Dec 18 23:01:26 Puter kernel: [ 8570.786410] [drm:radeon_crtc_page_flip], flip-ioctl() cur_fbo = ffff880bff782800, cur_bbo = ffff8805fe615400
Dec 18 23:01:27 Puter kernel: [ 8571.122775] [drm:drm_mode_addfb], [FB:51]
Dec 18 23:01:27 Puter kernel: [ 8571.122781] [drm:radeon_crtc_page_flip], flip-ioctl() cur_fbo = ffff8805fe615400, cur_bbo = ffff880bff782800
Dec 18 23:01:27 Puter kernel: [ 8571.122794] [drm:radeon_crtc_page_flip], flip-ioctl() cur_fbo = ffff8805fe615400, cur_bbo = ffff880bff782800
Dec 18 23:01:27 Puter kernel: [ 8571.667217] [drm:drm_mode_addfb], [FB:50]
Dec 18 23:01:27 Puter kernel: [ 8571.667224] [drm:radeon_crtc_page_flip], flip-ioctl() cur_fbo = ffff880bff782800, cur_bbo = ffff8805fe615400
Dec 18 23:01:27 Puter kernel: [ 8571.667236] [drm:radeon_crtc_page_flip], flip-ioctl() cur_fbo = ffff880bff782800, cur_bbo = ffff8805fe615400
Dec 18 23:01:28 Puter kernel: [ 8572.488325] [drm:drm_mode_addfb], [FB:51]
Dec 18 23:01:28 Puter kernel: [ 8572.488332] [drm:radeon_crtc_page_flip], flip-ioctl() cur_fbo = ffff8805fe615400, cur_bbo = ffff880bff782800
Dec 18 23:01:28 Puter kernel: [ 8572.488344] [drm:radeon_crtc_page_flip], flip-ioctl() cur_fbo = ffff8805fe615400, cur_bbo = ffff880bff782800
Dec 20 20:59:56 Puter kernel: [ 0.000000] Initializing cgroup subsys cpuset
Dec 20 20:59:56 Puter kernel: [ 0.000000] Initializing cgroup subsys cpu
Dec 20 20:59:56 Puter kernel: [ 0.000000] Initializing cgroup subsys cpuacct
Dec 20 20:59:56 Puter kernel: [ 0.000000] Linux version 3.13.0-74-generic (buildd@lcy01-07) (gcc version 4.8.2 (Ubuntu 4.8.2-19ubuntu1) ) #118-Ubuntu SMP Thu Dec 17 22:52:10 UTC 2015 (Ubuntu 3.13.0-74.118-generic 3.13.11-ckt30)
Dec 20 20:59:56 Puter kernel: [ 0.000000] Command line: BOOT_IMAGE=/vmlinuz-3.13.0-74-generic root=/dev/mapper/ubuntu--vg-root ro recovery nomodeset
Dec 20 20:59:56 Puter kernel: [ 0.000000] KERNEL supported cpus:
Dec 20 20:59:56 Puter kernel: [ 0.000000] Intel GenuineIntel
Dec 20 20:59:56 Puter kernel: [ 0.000000] AMD AuthenticAMD
Dec 20 20:59:56 Puter kernel: [ 0.000000] Centaur CentaurHauls
Dec 20 20:59:56 Puter kernel: [ 0.000000] e820: BIOS-provided physical RAM map:
Dec 20 20:59:56 Puter kernel: [ 0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009e3ff] usable
Dec 20 20:59:56 Puter kernel: [ 0.000000] BIOS-e820: [mem 0x00000000000f0000-0x00000000000fffff] reserved
Dec 20 20:59:56 Puter kernel: [ 0.000000] BIOS-e820: [mem 0x0000000000100000-0x00000000dbdf9bff] usable
Dec 20 20:59:56 Puter kernel: [ 0.000000] BIOS-e820: [mem 0x00000000dbdf9c00-0x00000000dbe4bbff] ACPI NVS
Dec 20 20:59:56 Puter kernel: [ 0.000000] BIOS-e820: [mem 0x00000000dbe4bc00-0x00000000dbe4dbff] ACPI data
Dec 20 20:59:56 Puter kernel: [ 0.000000] BIOS-e820: [mem 0x00000000dbe4dc00-0x00000000dbffffff] reserved
Dec 20 20:59:56 Puter kernel: [ 0.000000] BIOS-e820: [mem 0x00000000f8000000-0x00000000fcffffff] reserved
Dec 20 20:59:56 Puter kernel: [ 0.000000] BIOS-e820: [mem 0x00000000fe000000-0x00000000fed003ff] reserved
Dec 20 20:59:56 Puter kernel: [ 0.000000] BIOS-e820: [mem 0x00000000fee00000-0x00000000feefffff] reserved
Dec 20 20:59:56 Puter kernel: [ 0.000000] BIOS-e820: [mem 0x00000000ffb00000-0x00000000ffffffff] reserved
Dec 20 20:59:56 Puter kernel: [ 0.000000] BIOS-e820: [mem 0x0000000100000000-0x0000000c23ffffff] usable
Dec 20 20:59:56 Puter kernel: [ 0.000000] NX (Execute Disable) protection: active
Dec 20 20:59:56 Puter kernel: [ 0.000000] SMBIOS 2.5 present.
Dec 20 20:59:56 Puter kernel: [ 0.000000] DMI: Dell Inc. Precision WorkStation T7500 /0D881F, BIOS A14 07/06/2012
Dec 20 20:59:56 Puter kernel: [ 0.000000] e820: update [mem 0x00000000-0x00000fff] usable ==> reserved
Dec 20 20:59:56 Puter kernel: [ 0.000000] e820: remove [mem 0x000a0000-0x000fffff] usable
Dec 20 20:59:56 Puter kernel: [ 0.000000] No AGP bridge found
Dec 20 20:59:56 Puter kernel: [ 0.000000] e820: last_pfn = 0xc24000 max_arch_pfn = 0x400000000
Dec 20 20:59:56 Puter kernel: [ 0.000000] MTRR default type: write-back
任何想法都非常感谢！
进一步编辑
在谷歌上进一步搜索后，我偶然发现了此错误报告建议进行编辑etc/default/grub以删除 DRM 调试标记。我现在已经这样做了，只有时间才能证明它是否有效果。
另一处编辑：
经过长时间的稳定后，这种情况又发生了 - 我不能 100% 确定，但似乎每次 Ubuntu 运行 Ubuntu Core（我认为这是内核的另一种说法）的更新时都会发生这种情况。完全死机了，必须硬重置它，但如果我从 Grub 选择正常启动选项（它只会在系统上次启动失败时弹出）它就会正常工作，就像什么都没发生一样。
我不禁怀疑内核更新是否会在 Grub 配置中设置一些从旧安装中遗留的参数（例如，当我有不同的 gfx 卡时），并且只有当启动失败时，grub 才会因为失败而设置一些略有不同的参数，然后它才能顺利通过。
按照建议的做法egrep -B75 '\[ 0.000000\] Linux version' /var/log/kern.log*却没有任何效果！
我将看看是否有办法在系统上进行全新 Ubuntu 安装而不会丢失已安装的程序/设置，看看是否能解决问题 - 同时欢迎提出任何建议！
答案1
好吧，我不确定这算不算一个很好的答案，而且这肯定不是一个明确的解决方案/根本原因，但我已经受够了，转而使用 Linux Mint，现在它似乎更可靠了。也许安装程序将 grub 更新为更可靠的版本或类似的东西。
至少它对我有用。