Update 15.04 - 15.10

[eLdaYs]

Добрый вечер.
Обновил систему, после перезагрузки все хорошо запустилось, после повторного ребута система не загрузилась. Выдало сообщение "The system is running in low-graphics mode". Удалил xorg.conf, после ребута он создает новый:

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Section "ServerLayout"
    Identifier "layout"
    Screen 0 "nvidia"
    Inactive "intel"
EndSection

Section "Device"
    Identifier "intel"
    Driver "modesetting"
    BusID "PCI:0@0:2:0"
    Option "AccelMethod" "None"
EndSection

Section "Screen"
    Identifier "intel"
    Device "intel"
EndSection

Лог xorg.conf:

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[    24.511]
X.Org X Server 1.17.2
Release Date: 2015-06-16
[    24.511] X Protocol Version 11, Revision 0
[    24.511] Build Operating System: Linux 3.13.0-68-generic x86_64 Ubuntu
[    24.511] Current Operating System: Linux acer 3.19.0-39-generic #44-Ubuntu SMP Tue Dec 1 14:39:05 UTC 2015 x86_64
[    24.511] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-3.19.0-39-generic root=UUID=de0cb989-52fb-47af-a41d-17b81aba4b3f ro quiet splash video.use_native_backlight=1 vt.handoff=7 nomodeset
[    24.511] Build Date: 12 November 2015  05:33:29PM
[    24.512] xorg-server 2:1.17.2-1ubuntu9.1 (For technical support please see http://www.ubuntu.com/support)
[    24.512] Current version of pixman: 0.32.6
[    24.512]    Before reporting problems, check http://wiki.x.org
   to make sure that you have the latest version.
[    24.512] Markers: (--) probed, (**) from config file, (==) default setting,
   (++) from command line, (!!) notice, (II) informational,
   (WW) warning, (EE) error, (NI) not implemented, (??) unknown.
[    24.512] (==) Log file: "/var/log/Xorg.0.log", Time: Sat Dec 12 20:52:49 2015
[    24.512] (==) Using config file: "/etc/X11/xorg.conf"
[    24.512] (==) Using system config directory "/usr/share/X11/xorg.conf.d"
[    24.537] Data incomplete in file /etc/X11/xorg.conf
   Undefined Screen "nvidia" referenced by ServerLayout "layout".
[    24.537] (EE) Problem parsing the config file
[    24.537] (EE) Error parsing the config file
[    24.537] (EE)
Fatal server error:
[    24.537] (EE) no screens found(EE)
[    24.537] (EE)
Please consult the The X.Org Foundation support
    at http://wiki.x.org
 for help.
[    24.537] (EE) Please also check the log file at "/var/log/Xorg.0.log" for additional information.
[    24.537] (EE)
[    24.537] (EE) Server terminated with error (1). Closing log file.

Удалил все внутри и запретил запись с помощью команды:

Код: [Выделить]

chattr +i /etc/X11/xorg.confСистема запустилась до ввода логина и пароля, после ввода он показывает фоновую картинку и сбрасывает все назад, в гостевом режиме заходит. 
Лог lightdm:

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[+0.03s] DEBUG: Logging to /var/log/lightdm/lightdm.log
[+0.03s] DEBUG: Starting Light Display Manager 1.16.6, UID=0 PID=1268
[+0.03s] DEBUG: Loading configuration dirs from /usr/share/lightdm/lightdm.conf.d
[+0.03s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-greeter-wrapper.conf
[+0.03s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-guest-wrapper.conf
[+0.03s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-ubuntu.conf
[+0.03s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-unity-greeter.conf
[+0.03s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/50-xserver-command.conf
[+0.03s] DEBUG: Loading configuration dirs from /usr/local/share/lightdm/lightdm.conf.d
[+0.03s] DEBUG: Loading configuration dirs from /etc/xdg/lightdm/lightdm.conf.d
[+0.03s] DEBUG: Loading configuration from /etc/lightdm/lightdm.conf
[+0.03s] DEBUG:   [SeatDefaults] is now called [Seat:*], please update this configuration
[+0.03s] DEBUG: Using D-Bus name org.freedesktop.DisplayManager
[+0.03s] DEBUG: Registered seat module xlocal
[+0.03s] DEBUG: Registered seat module xremote
[+0.03s] DEBUG: Registered seat module unity
[+0.03s] DEBUG: Monitoring logind for seats
[+0.03s] DEBUG: New seat added from logind: seat0
[+0.03s] DEBUG: Seat seat0: Loading properties from config section Seat:*
[+0.03s] DEBUG: Seat seat0: Starting
[+0.03s] DEBUG: Seat seat0: Creating user session
[+0.03s] DEBUG: Loading users from org.freedesktop.Accounts
[+0.03s] DEBUG: User /org/freedesktop/Accounts/User1000 added
[+0.03s] DEBUG: Seat seat0: Can't login unknown user 'ubuntu'
[+0.03s] DEBUG: Seat seat0: Creating greeter session
[+0.03s] DEBUG: Seat seat0: Creating display server of type x
[+0.04s] DEBUG: Quitting Plymouth
[+0.06s] DEBUG: Using VT 7
[+0.06s] DEBUG: Seat seat0: Starting local X display on VT 7
[+0.06s] DEBUG: DisplayServer x-0: Logging to /var/log/lightdm/x-0.log
[+0.06s] DEBUG: DisplayServer x-0: Writing X server authority to /var/run/lightdm/root/:0
[+0.06s] DEBUG: DisplayServer x-0: Launching X Server
[+0.06s] DEBUG: Launching process 1282: /usr/bin/X -core :0 -seat seat0 -auth /var/run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch
[+0.06s] DEBUG: DisplayServer x-0: Waiting for ready signal from X server :0
[+0.06s] DEBUG: Acquired bus name org.freedesktop.DisplayManager
[+0.06s] DEBUG: Registering seat with bus path /org/freedesktop/DisplayManager/Seat0
[+1.88s] DEBUG: Process 1282 terminated with signal 6
[+1.88s] DEBUG: DisplayServer x-0: X server stopped
[+1.88s] DEBUG: Releasing VT 7
[+1.88s] DEBUG: DisplayServer x-0: Removing X server authority /var/run/lightdm/root/:0
[+1.88s] DEBUG: Seat seat0: Display server stopped
[+1.88s] DEBUG: Seat seat0: Stopping; greeter display server failed to start
[+1.88s] DEBUG: Seat seat0: Stopping
[+1.88s] DEBUG: Seat seat0: Stopping session
[+1.88s] DEBUG: Seat seat0: Session stopped
[+1.88s] DEBUG: Seat seat0: Stopped
[+1.88s] DEBUG: Required seat has stopped
[+1.88s] DEBUG: Stopping display manager
[+1.88s] DEBUG: Display manager stopped
[+1.88s] DEBUG: Stopping daemon
[+1.88s] DEBUG: Seat seat0: Stopping session
[+1.88s] DEBUG: Exiting with return value 1

Была еще такая ошибка: [drm:intel.pipe.config.compare[i915]] *ERROR* mismatch in ips.enable (experted 1, found 0)
Запустился со старого ядра ошибка пропала.
Ноутбук: Acer aspire e 17, Intel Core i-4210U, Nvidia GeForce 840m 2gb
Может кто сталкивался с такой проблемой, уже не знаю что и делать 

[kuguar]

я такую же фигню словил после отката с 15.10 до 15.04 .
 Похоже, косяк в новом ядре.
Откатывался, потому что на 15.10 kodi незавелся по каким-то дурацким причинам. аппарат intel NUK.

[eLdaYs]

Ставил чистую 15,10. Установил Bumblebee, история повторилась. Не грузились иксы, создавался xorg.conf. Поставил обратно 15,04 

[serchik]

Ставил чистую 15,10. Установил Bumblebee, история повторилась. Не грузились иксы, создавался xorg.conf. Поставил обратно 15,04 

Отвыкайте от переустановки системы, если у Вас что-то перестало работать! Накатывайте проприетарные драйвера для дискретной видеокарты и проблема отпадет.