I am a new user of scientific linux 6 .
I am working on a project started by others and Unfortunatly , the GUI stopped working.
I need to find out how to trouble shoot the GUI to solve the problem .
What I have now When I open my PC is a complete black terminal .
I need to go back to the GUI and start troubleshooting.
Can somebody advice me how to start ?
Thanks

Welcome to Linux Questions!

Did you do any update resulting in this problem?

You may try reinstalling GUI packages.

Does Xorg starts? Can you atleast login in a VT (Virtual Terminal)?

you can also check logfiles (as root) in /var/log

question 1 of ?

1)
what GUI?
2)
are you referring to the program?
3)
or to the Desktop?
4)
if desktop
Gnome2
KDE4
xfce
lxde
other

5)
the program?
or the desktop?

6)
whay is it built on ?
GTK ?
QT ? (qt 3 or qt4 or qt5 )
SDL ?
ncurs ?

what ?

7)
What has changed ?

What desktop and what changed ?

[/COLOR]


I Did
#yum update.
#Xorg -configure : gives the error ( Missing output drivers. Configuration failed )

I tried also
#xinit : it gives errors ( no screens found )

Any ideas that may help ?
thanks

#ls /var/log
Gives a list of log files .
Sorry , Kindly explain what I can do with them to be able to open the GUI ?

The Desktop doesn't open at all .. Once I turn on my Computer , Scientific linux logo starts to load to infinity and never opens the desktop .
I pressed Alt+F2 to start the terminal and then
# xinit : No screens found
kind of desktop ... How can I know ? ( Sorry I know very little of linux and started by facing this problem ! )

Hope you can help

What graphics card/chip you have? Post the output of 'lspci' here.

Post the ouput of command 'ls /usr/lib/xorg/modules/drivers' here.

Can you run 'startx'? If it starts then it would produce a log. Post this log.

Give the exact output, when 'Xorg -configure' was run. See your current directory to see a file named 'xorg.conf.new' produced. Check it.

And post for all answer/steps listed here.

#lspci اgrep VGA
( 00:02.0 VGA compatible controller : Intel Corporation Xeon E3 v3/4th Gen Core Processor Integrated Graphics controller ( rev 06)

#ls /usr/lib/xorg/modules/drivers
( ls : cannot access /usr/lib/xorg/modules/drivers : No such file or directory )

#startx
[[[
(==) Log file: "/var/log/Xorg.0.log", Time: Mon Apr 27 16:32:29 2015
(==) Using Config file : "/etc/X11/xorg.conf"
(==) Using system Config directory "/usr/share/X11/xorg.conf.d"
Initializing built-in extension Generic Event Extension
Initializing
...
..
.... ( NOTE : ... refers to lines Initializing built in , but I am un able to copy paste as I am using another computer to log onto the internet , If you think they are important to be posted here , I would write them

(EE)
Fatal server error :
(EE) no screens found(EE)
(EE)
Please consult the Scientific linux support at http://www.scientificlinux.org/maillists for help .
(EE) Please also check the log file at " /var/log/Xorg.0.log" for additional information.
(EE)
(EE) Server terminated with error (1). Closing log file .
giving up.
xinit: Connection refused ( errno 111) : unable to connect to Xserver
xinit: No Such process (errno 3) : Server error.

]]]


#Xorg -configure
[[[
X.Org X server 1.15.0
Release Date:
Xprotocol Version 11, Revision 0
Build Operating System: s16 2.6.32-504.e16.x86_64
Current operating System : Linux master.fci 2.6.32-504.e16.x86_64 #1 SMP Tue jan 27 13;39;10 CST 2015 x86-64
Kernel Command line: ro root=/dev/mapper/vg_master-lv_root rd_NO_LUKS KEYBOARDTYPE=pc KEYTABLE=us LANG=en_US.UTF-8 rd_NO_MD
rg_LVM_LV=vg_master/lv_swap SYSFONT=latarcyrheb=sun16 rd_LVM_LV=vg_master/lv_root rd_NO_DM rd_NO_DM rhgb quiet crashkernel=131M@0M
Build Date: 11 December 2014 01:54:26PM
Build ID : xorg-X11-server 1.15.0-25.s16
Current version of pixman: 0.32.4
Before reporting problems , check http://www.scientificlinux.org/maillists
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: Mon Apr 27 16:49:53 2015
Missing output drivers. Configuration failed
(EE) Server terminated with error (2). Closing log file.
]]]

" See your current directory to see a file named 'xorg.conf.new' produced. Check it."
#nano /etc/xorg.conf.new
[ opens an empty file ]

Thanks for your help

I am not familiar with this distro but I do have some experience with Redhat/Fedora and rpm.

It appears the xorg drivers for graphics and may be other hardware is missing.

Please post the output of:

Do some research on xorg graphics and input drivers.

#rpm -qa | grep xorg
xorg-x11-server-utils-7.7-2.e16.x86_64
xorg-x11-xinit-1.0.9-14.e16.x86_64
xorg-x11-xkb-utils-7.7-4.e16.x86_64
Xorg-x11-server-Xorg-1.15.0-25.s16.x86_64
xorg-x11-proto-devel-7.7-9.e16.noarch
xorg-x11-docs-1.3-6.1.e16.noarch
xorg-x11-xauth-1.0.2-7.1.e16.x86_64
xorg-x11-drv-wacom-0.23.0-4.e16.x86_64
xorg-x11-font-utils-7.2-11.e16.x86_64
xorg-x11-drv-ati-firmware-7.3.99-2.e16.noarch
xorg-x11-server-common-1.15.0-26.s16.x86_64

hope that can help
many thanks

So the problem is you don't have xorg driver for

1) Intel chip you have as VGA.

2) Input driver for keyboards and mouse.

So install those xorg drivers from your installation cd/dvd disc or a repository. Note all drivers package start with 'xorg-'.

Well, with a VGA only chipset, most of the more recent GUI (Gnome, Cinnamon, and maybe even Mate) will not work. They are using GL capable hardware acceleration, which is not available with VGA only.

Might have to try something simpler like LXDE or Xfce.

But the GUI was working well at first .. Why did it stop now ?
How can I install these xorg drives from a repository ?
What shall I do certainly ? What command lines can be used for the installation ?

Many thanks for your help

---------- Post added 04-28-15 at 03:58 AM ----------

How ?

Frequently, you would have to install them from the distribution first.

Since SL is based on RH, they should be in the repository (package groups like "LXDE Desktop", "Xfce Desktop" - note, I'm working from a Fedora release, so you have to check the list of desktops in the repository - "yum group list" should list all the available package groups including the desktops)

Then install it by 'yum groupinstall "<chosen group>"'.

Normally, this should be sufficient. Sometimes the GUI login isn't included causing issues, but I think that has been a packaging error. At a minimum, the old standby xdm can be used (should be in the package xorg-x11-xdm).