我知道我不是第一个遇到这个问题的人。我已经在网上搜索了好几天，尝试了所有建议的解决方案，但对我都没有用。
我的系统：
我正在运行 Ubuntu 16.04，
linux - linux系统grep -i vga
00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09)
01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Whistler [Radeon HD 6730M/6770M/7690M XT] (rev ff)
问题：
我尝试启动我的机器。grub 出现，我可以选择 Ubuntu。Ubuntu 加载屏幕出现。接下来，出现“系统正在低图形模式下运行”窗口。我可以单击“确定”（使用按键，鼠标不显示）并在下一个窗口中选择其中一个选项，但它们都不会带我去任何地方，只能回到同一个窗口。我可以使用 [ctl]+[alt]+[F1] 打开 tty。
让我发布一些日志文件：
/var/log/lightdm/lightdm.log：
[+0.09s] DEBUG: Logging to /var/log/lightdm/lightdm.log
[+0.09s] DEBUG: Starting Light Display Manager 1.18.3, UID=0 PID=1205
[+0.09s] DEBUG: Loading configuration dirs from /usr/share/lightdm/lightdm.conf.d
[+0.09s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-disable-log-backup.conf
[+0.09s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-greeter-wrapper.conf
[+0.09s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-guest-wrapper.conf
[+0.09s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-session-wrapper.conf
[+0.09s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-ubuntu.conf
[+0.09s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-unity-greeter.conf
[+0.09s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-xserver-command.conf
[+0.09s] DEBUG: Loading configuration dirs from /usr/local/share/lightdm/lightdm.conf.d
[+0.09s] DEBUG: Loading configuration dirs from /etc/xdg/lightdm/lightdm.conf.d
[+0.09s] DEBUG: Loading configuration from /etc/lightdm/lightdm.conf
[+0.09s] DEBUG: Using D-Bus name org.freedesktop.DisplayManager
[+0.09s] DEBUG: Registered seat module xlocal
[+0.09s] DEBUG: Registered seat module xremote
[+0.09s] DEBUG: Registered seat module unity
[+0.09s] DEBUG: Monitoring logind for seats
[+0.09s] DEBUG: New seat added from logind: seat0
[+0.09s] DEBUG: Seat seat0: Loading properties from config section Seat:*
[+0.09s] DEBUG: Seat seat0: Starting
[+0.09s] DEBUG: Seat seat0: Creating greeter session
[+0.24s] DEBUG: Seat seat0: Creating display server of type x
[+0.26s] DEBUG: Quitting Plymouth
[+0.28s] DEBUG: Using VT 7
[+0.28s] DEBUG: Seat seat0: Starting local X display on VT 7
[+0.28s] DEBUG: DisplayServer x-0: Logging to /var/log/lightdm/x-0.log
[+0.28s] DEBUG: DisplayServer x-0: Writing X server authority to /var/run/lightdm/root/:0
[+0.28s] DEBUG: DisplayServer x-0: Launching X Server
[+0.28s] DEBUG: Launching process 1215: /usr/bin/X -core :0 -seat seat0 -auth /var/run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch
[+0.28s] DEBUG: DisplayServer x-0: Waiting for ready signal from X server :0
[+0.28s] DEBUG: Acquired bus name org.freedesktop.DisplayManager
[+0.28s] DEBUG: Registering seat with bus path /org/freedesktop/DisplayManager/Seat0
[+0.50s] DEBUG: Loading users from org.freedesktop.Accounts
[+0.50s] DEBUG: User /org/freedesktop/Accounts/User1000 added
[+6.21s] DEBUG: Got signal 10 from process 1215
[+6.21s] DEBUG: DisplayServer x-0: Got signal from X server :0
[+6.21s] DEBUG: DisplayServer x-0: Connecting to XServer :0
[+6.21s] DEBUG: Seat seat0: Display server ready, starting session authentication
[+6.21s] DEBUG: Session pid=1278: Started with service 'lightdm-greeter', username 'lightdm'
[+6.21s] DEBUG: Greeter closed communication channel
[+6.21s] DEBUG: Session pid=1278: Exited with return value 1
[+6.21s] DEBUG: Session: Failed during authentication
[+6.21s] DEBUG: Seat seat0: Stopping session that failed authentication
[+6.21s] DEBUG: Seat seat0: Session stopped
[+6.21s] DEBUG: Seat seat0: Stopping; failed to start a greeter
[+6.21s] DEBUG: Seat seat0: Stopping
[+6.21s] DEBUG: Seat seat0: Stopping display server
[+6.21s] DEBUG: Sending signal 15 to process 1215
[+6.50s] DEBUG: Process 1215 exited with return value 0
[+6.50s] DEBUG: DisplayServer x-0: X server stopped
[+6.50s] DEBUG: Releasing VT 7
[+6.50s] DEBUG: DisplayServer x-0: Removing X server authority /var/run/lightdm/root/:0
[+6.50s] DEBUG: Seat seat0: Display server stopped
[+6.50s] DEBUG: Seat seat0: Stopped
[+6.50s] DEBUG: Required seat has stopped
[+6.50s] DEBUG: Stopping display manager
[+6.50s] DEBUG: Display manager stopped
[+6.50s] DEBUG: Stopping daemon
[+6.50s] DEBUG: Exiting with return value 1
/var/log/x-0.log：
X.Org X Server 1.18.4
Release Date: 2016-07-19
X Protocol Version 11, Revision 0
Build Operating System: Linux 4.4.0-45-generic x86_64 Ubuntu
Current Operating System: Linux FabisLaptop 4.4.0-59-generic #80-Ubuntu SMP Fri Jan 6 17:47:47 UTC 2017 x86_64
Kernel command line: BOOT_IMAGE=/boot/vmlinuz-4.4.0-59-generic root=UUID=cbeafd2d-ead6-4060-a2ae-caca82c11c76 ro quiet splash vt.handoff=7
Build Date: 02 November 2016 10:06:10PM
xorg-server 2:1.18.4-0ubuntu0.2 (For technical support please see http://www.ubuntu.com/support)
Current version of pixman: 0.33.6
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.0.log", Time: Fri Jan 27 14:22:26 2017
(==) Using config file: "/etc/X11/xorg.conf"
(==) Using system config directory "/usr/share/X11/xorg.conf.d"
(II) [KMS] Kernel modesetting enabled.
The XKEYBOARD keymap compiler (xkbcomp) reports:
> Warning: Type "ONE_LEVEL" has 1 levels, but <RALT> has 2 symbols
> Ignoring extra symbols
Errors from xkbcomp are not fatal to the X server
(II) Server terminated successfully (0). Closing log file.
/var/log/Xorg.0.log：
我不得不从我的帖子中删除这个文件，因为它太长了。如果需要，我可以在另一条评论中提供它，但我无论如何都找不到任何可疑的东西。该文件的结尾与上一个文件相同：
[ 40.876] (II) Server terminated successfully (0). Closing log file.
类似于 lightdm 尝试启动会话，但立即失败。没有 ~/.Xsession-errors
配置：
在 /usr/share/lightdm/lightdm.conf.d 中有一些文件每个只包含一个参数。这些是：
greeter-wrapper=/usr/lib/lightdm/lightdm-greeter-session
guest-wrapper=/usr/lib/lightdm/lightdm-guest-session
session-wrapper=/usr/sbin/lightdm-session
user-session=ubuntu
greeter-session=unity-greeter
xserver-command=X -core
backup-logs=false
xorg.conf：
Section "ServerLayout"
Identifier "X.org Configured"
Screen 0 "Screen0" 0 0
Screen 1 "Screen1" RightOf "Screen0"
InputDevice "Mouse0" "CorePointer"
InputDevice "Keyboard0" "CoreKeyboard"
EndSection
Section "Files"
ModulePath "/usr/lib/xorg/modules"
FontPath "/usr/share/fonts/X11/misc"
FontPath "/usr/share/fonts/X11/cyrillic"
FontPath "/usr/share/fonts/X11/100dpi/:unscaled"
FontPath "/usr/share/fonts/X11/75dpi/:unscaled"
FontPath "/usr/share/fonts/X11/Type1"
FontPath "/usr/share/fonts/X11/100dpi"
FontPath "/usr/share/fonts/X11/75dpi"
FontPath "built-ins"
EndSection
Section "Module"
Load "glx"
EndSection
Section "InputDevice"
Identifier "Keyboard0"
Driver "kbd"
EndSection
Section "InputDevice"
Identifier "Mouse0"
Driver "mouse"
Option "Protocol" "auto"
Option "Device" "/dev/input/mice"
Option "ZAxisMapping" "4 5 6 7"
EndSection
Section "Monitor"
Identifier "Monitor0"
VendorName "Monitor Vendor"
ModelName "Monitor Model"
EndSection
Section "Monitor"
Identifier "Monitor1"
VendorName "Monitor Vendor"
ModelName "Monitor Model"
EndSection
Section "Device"
### Available Driver options are:-
### Values: <i>: integer, <f>: float, <bool>: "True"/"False",
### <string>: "String", <freq>: "<f> Hz/kHz/MHz",
### <percent>: "<f>%"
### [arg]: arg optional
#Option "Accel" # [<bool>]
#Option "AccelMethod" # <str>
#Option "Backlight" # <str>
#Option "CustomEDID" # <str>
#Option "DRI" # <str>
#Option "Present" # [<bool>]
#Option "ColorKey" # <i>
#Option "VideoKey" # <i>
#Option "Tiling" # [<bool>]
#Option "LinearFramebuffer" # [<bool>]
#Option "HWRotation" # [<bool>]
#Option "VSync" # [<bool>]
#Option "PageFlip" # [<bool>]
#Option "SwapbuffersWait" # [<bool>]
#Option "TripleBuffer" # [<bool>]
#Option "XvPreferOverlay" # [<bool>]
#Option "HotPlug" # [<bool>]
#Option "ReprobeOutputs" # [<bool>]
#Option "XvMC" # [<bool>]
#Option "ZaphodHeads" # <str>
#Option "VirtualHeads" # <i>
#Option "TearFree" # [<bool>]
#Option "PerCrtcPixmaps" # [<bool>]
#Option "FallbackDebug" # [<bool>]
#Option "DebugFlushBatches" # [<bool>]
#Option "DebugFlushCaches" # [<bool>]
#Option "DebugWait" # [<bool>]
#Option "BufferCache" # [<bool>]
Identifier "Card0"
Driver "intel"
BusID "PCI:0:2:0"
EndSection
Section "Device"
### Available Driver options are:-
### Values: <i>: integer, <f>: float, <bool>: "True"/"False",
### <string>: "String", <freq>: "<f> Hz/kHz/MHz",
### <percent>: "<f>%"
### [arg]: arg optional
#Option "Accel" # [<bool>]
#Option "SWcursor" # [<bool>]
#Option "EnablePageFlip" # [<bool>]
#Option "ColorTiling" # [<bool>]
#Option "ColorTiling2D" # [<bool>]
#Option "RenderAccel" # [<bool>]
#Option "SubPixelOrder" # [<str>]
#Option "AccelMethod" # <str>
#Option "ShadowPrimary" # [<bool>]
#Option "EXAVSync" # [<bool>]
#Option "EXAPixmaps" # [<bool>]
#Option "ZaphodHeads" # <str>
#Option "SwapbuffersWait" # [<bool>]
#Option "DeleteUnusedDP12Displays" # [<bool>]
#Option "DRI3" # [<bool>]
#Option "DRI" # <i>
#Option "TearFree" # [<bool>]
Identifier "Card1"
Driver "radeon"
BusID "PCI:1:0:0"
EndSection
Section "Screen"
Identifier "Screen0"
Device "Card0"
Monitor "Monitor0"
SubSection "Display"
Viewport 0 0
Depth 1
EndSubSection
SubSection "Display"
Viewport 0 0
Depth 4
EndSubSection
SubSection "Display"
Viewport 0 0
Depth 8
EndSubSection
SubSection "Display"
Viewport 0 0
Depth 15
EndSubSection
SubSection "Display"
Viewport 0 0
Depth 16
EndSubSection
SubSection "Display"
Viewport 0 0
Depth 24
EndSubSection
EndSection
Section "Screen"
Identifier "Screen1"
Device "Card1"
Monitor "Monitor1"
SubSection "Display"
Viewport 0 0
Depth 1
EndSubSection
SubSection "Display"
Viewport 0 0
Depth 4
EndSubSection
SubSection "Display"
Viewport 0 0
Depth 8
EndSubSection
SubSection "Display"
Viewport 0 0
Depth 15
EndSubSection
SubSection "Display"
Viewport 0 0
Depth 16
EndSubSection
SubSection "Display"
Viewport 0 0
Depth 24
EndSubSection
EndSection
到目前为止我尝试过的
- 将 .Xauthority 和 .ICEauthority 的权限和所有权更改为 664 和用户：用户
- 重新配置 lightdm dpgk-重新配置 lightdm
- 尝试另一个接待员
- 卸载 ati 驱动程序并重新安装 radeon 驱动程序 apt-get install xserver-xorg-video-radeon
- 删除几个文件： rm -r ~/.config（例如移至备份） rm ~/.xsession-errors rm ~/.*authority rm /etc/X11/xorg.conf
- 重新安装 ubuntu-desktop execstack dh-modaliases debhelper
- 确保对多个库的所有权 chown lightdm:lightdm -R /var/lib/lightdm chown avahi-autoipd:avahi-autoipd -R /var/lib/avahi-autoipd chown colord:colord -R /var/lib/colord
- 尝试使用“xforcevasa”选项启动
- 尝试 gdm3 而不是 lightdm
这有效。有点……
从 tty 我可以执行以下操作：
sudo startx
sudo dconf reset -f /org/compiz
sudo gsettings reset-recursively org.compiz
sudo setsid unity
sudo unity --reset-icons
所有这些一起带回了统一的图形界面。左侧的启动器可用，唯一缺少的是顶部状态栏中的图标（关机、wifi 等）。此外，现在我以 root 身份登录，而不是以我的用户身份登录。也许是因为我将“sudo”用于“setsid unity”……？
恢复 GUI 后，我还可以启动 ccsm 并确保“Ubuntu Unity 插件”已启用。
现在我毕竟已经没有什么主意了。我不知道还能尝试什么。
请帮我！