之后aptitude safe-upgrade我的笔记本电脑不再启动。
我记录了这个视频的启动过程。
我可以访问 tty1，从那里我可以运行startx它，没有问题。这是输出：
X.Org X Server 1.17.2
Release Date: 2015-06-16
X Protocol Version 11, Revision 0
Build Operating System: Linux 4.1.0 x86_64 Debian
Current Operating System: Linux debian 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt11-1 (2015-05-24) x86_64
Kernel command line: BOOT_IMAGE=/vmlinuz-3.16.0-4-amd64 root=/dev/mapper/debian--vg-root ro quiet
Build Date: 11 August 2015 10:51:15AM
xorg-server 2:1.17.2-1.1 (http://www.debian.org/support)
Current version of pixman: 0.32.6
Before reporting problems, check http://wiki.x.org
to make sure that you have the latest version.
Markers: (--) probed, (**) from config file, (==) default setting,
(++) from command line, (!!) notice, (II) informational,
(WW) warning, (EE) error, (NI) not implemented, (??) unknown.
(==) Log file: "/var/log/Xorg.2.log", Time: Fri Aug 28 15:55:04 2015
(==) Using system config directory "/usr/share/X11/xorg.conf.d"
我认为问题可能出在 DM 上。这是/var/lightdm/lightdm.log输出：
[+0.00s] DEBUG: Logging to /var/log/lightdm/lightdm.log
[+0.00s] DEBUG: Starting Light Display Manager 1.14.2, UID=0 PID=1275
[+0.00s] DEBUG: Loading configuration dirs from /usr/share/lightdm/lightdm.conf.d
[+0.00s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/01_debian.conf
[+0.00s] DEBUG: Loading configuration dirs from /usr/local/share/lightdm/lightdm.conf.d
[+0.00s] DEBUG: Loading configuration dirs from /etc/xdg/lightdm/lightdm.conf.d
[+0.00s] DEBUG: Loading configuration from /etc/lightdm/lightdm.conf
[+0.00s] DEBUG: Using D-Bus name org.freedesktop.DisplayManager
[+0.00s] DEBUG: Registered seat module xlocal
[+0.00s] DEBUG: Registered seat module xremote
[+0.00s] DEBUG: Registered seat module unity
[+0.01s] DEBUG: Monitoring logind for seats
[+0.01s] DEBUG: New seat added from logind: seat0
[+0.01s] DEBUG: Loading properties from config section SeatDefaults
[+0.01s] DEBUG: Seat seat0: Starting
[+0.01s] DEBUG: Seat seat0: Creating greeter session
[+0.01s] DEBUG: Seat seat0: Creating display server of type x
[+0.01s] DEBUG: Could not run plymouth --ping: Failed to execute child process "plymouth" (No such file or directory)
[+0.01s] DEBUG: Using VT 7
[+0.01s] DEBUG: Seat seat0: Starting local X display on VT 7
[+0.01s] DEBUG: DisplayServer x-0: Logging to /var/log/lightdm/x-0.log
[+0.01s] DEBUG: DisplayServer x-0: Writing X server authority to /var/run/lightdm/root/:0
[+0.01s] DEBUG: DisplayServer x-0: Launching X Server
[+0.01s] DEBUG: Launching process 1280: /usr/bin/X :0 -seat seat0 -auth /var/run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch
[+0.01s] DEBUG: DisplayServer x-0: Waiting for ready signal from X server :0
[+0.01s] DEBUG: Acquired bus name org.freedesktop.DisplayManager
[+0.01s] DEBUG: Registering seat with bus path /org/freedesktop/DisplayManager/Seat0
[+0.01s] DEBUG: Loading users from org.freedesktop.Accounts
[+0.02s] DEBUG: User /org/freedesktop/Accounts/User1000 added
[+0.35s] DEBUG: Got signal 10 from process 1280
[+0.35s] DEBUG: DisplayServer x-0: Got signal from X server :0
[+0.35s] DEBUG: DisplayServer x-0: Connecting to XServer :0
[+0.35s] DEBUG: Seat seat0: Display server ready, starting session authentication
[+0.35s] DEBUG: Session pid=1291: Started with service 'lightdm-greeter', username 'lightdm'
[+0.37s] DEBUG: Session pid=1291: Authentication complete with return value 0: Success
[+0.37s] DEBUG: Seat seat0: Session authenticated, running command
[+0.37s] DEBUG: Session pid=1291: Running command /usr/sbin/lightdm-gtk-greeter
[+0.37s] DEBUG: Creating shared data directory /var/lib/lightdm/data/lightdm
[+0.37s] DEBUG: Session pid=1291: Logging to /var/log/lightdm/x-0-greeter.log
[+0.42s] DEBUG: Activating VT 7
[+0.42s] DEBUG: Activating login1 session c7
[+0.42s] DEBUG: Seat seat0 changes active session to c7
[+0.42s] DEBUG: Session c7 is already active
[+0.50s] DEBUG: Session pid=1291: Greeter closed communication channel
[+0.50s] DEBUG: Session pid=1291: Exited with return value 0
[+0.50s] DEBUG: Seat seat0: Session stopped
[+0.50s] DEBUG: Seat seat0: Stopping; failed to start a greeter
[+0.50s] DEBUG: Seat seat0: Stopping
[+0.50s] DEBUG: Seat seat0: Stopping display server
[+0.50s] DEBUG: Sending signal 15 to process 1280
[+0.51s] DEBUG: Seat seat0 changes active session to
[+0.51s] CRITICAL: session_get_login1_session_id: assertion 'session != NULL' failed
[+1.52s] DEBUG: Process 1280 exited with return value 0
[+1.52s] DEBUG: DisplayServer x-0: X server stopped
[+1.52s] DEBUG: Releasing VT 7
[+1.52s] DEBUG: DisplayServer x-0: Removing X server authority /var/run/lightdm/root/:0
[+1.52s] DEBUG: Seat seat0: Display server stopped
[+1.52s] DEBUG: Seat seat0: Stopped
[+1.52s] DEBUG: Required seat has stopped
[+1.52s] DEBUG: Stopping display manager
[+1.52s] DEBUG: Display manager stopped
[+1.52s] DEBUG: Stopping daemon
[+1.52s] DEBUG: Exiting with return value 1
注意到下面这行了吗？
[+0.51s] CRITICAL: session_get_login1_session_id: assertion 'session != NULL' failed
Mate使用Lightdm，所以我删除并重新安装，但这没有任何区别。然后我安装了XLDE，它使用lxdm。再次出现同样的问题：屏幕闪烁和光标闪烁。
所以这与X无关，因为我可以手动启动x，而且与桌面环境无关，因为我对Mate和LXDE都有同样的问题。
有人建议我应该从哪里开始解决这个问题吗？
答案1
我一直在研究这个问题，显然解决这个问题的最佳方法是重新安装整个操作系统。
另外，如果您删除 lightdm 并再次安装它，您是否使用了apt-get remove lightdm或apt-get purge lightdm？清除也会删除所有配置文件。