Nvidia Ion Asus Eee PC Seashell серии 1215n и Оптимус

Я использую Ubuntu, Lubuntu, Kubuntu:

Linux sysop 3.19.0-33-generiC#38-Ubuntu SMP пт 6 ноября 18:18:12 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

на Asus Eee PC серии Seashell 1215n с картой Nvidia Ion. После установки следующих пакетов:

sudo apt-get install nvidia-346 nvidia-settings nvidia-prime

lightdm gdm sddm не запускается. Если я хочу получить графическое окружение, мне нужно: авторизоваться в tty, а затем сделать:

sudo nvidia-xconfig
startx

Может ли кто-нибудь помочь мне заставить менеджер рабочего стола работать?

здесь файл /var/log/Xorg.1.log:

[    32.369] 
X.Org X Server 1.17.1
Release Date: 2015-02-10
[    32.369] X Protocol Version 11, Revision 0
[    32.369] Build Operating System: Linux 3.19.0-28-generic x86_64 Ubuntu
[    32.369] Current Operating System: Linux sysop 3.19.0-33-generic #38-Ubuntu SMP Fri Nov 6 18:18:12 UTC 2015 x86_64
[    32.369] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-3.19.0-33-generic root=UUID=d414642e-6948-440a-a6cd-4fe8cc819dca ro
[    32.369] Build Date: 11 September 2015  10:30:58AM
[    32.370] xorg-server 2:1.17.1-0ubuntu3.1 (For technical support please see http://www.ubuntu.com/support) 
[    32.370] Current version of pixman: 0.32.6
[    32.370]    Before reporting problems, check http://wiki.x.org
    to make sure that you have the latest version.
[    32.370] Markers: (--) probed, (**) from config file, (==) default setting,
    (++) from command line, (!!) notice, (II) informational,
    (WW) warning, (EE) error, (NI) not implemented, (??) unknown.
[    32.370] (==) Log file: "/var/log/Xorg.1.log", Time: Sat Nov 14 09:17:13 2015
[    32.370] (==) Using config file: "/etc/X11/xorg.conf"
[    32.370] (==) Using system config directory "/usr/share/X11/xorg.conf.d"
[    32.371] Data incomplete in file /etc/X11/xorg.conf
    Undefined Screen "nvidia" referenced by ServerLayout "layout".
[    32.371] (EE) Problem parsing the config file
[    32.371] (EE) Error parsing the config file
[    32.372] (EE) 
Fatal server error:
[    32.372] (EE) no screens found(EE) 
[    32.372] (EE) 
Please consult the The X.Org Foundation support 
     at http://wiki.x.org
 for help. 
[    32.372] (EE) Please also check the log file at "/var/log/Xorg.1.log" for additional information.
[    32.372] (EE) 
[    32.372] (EE) Server terminated with error (1). Closing log file.