[CentOS] Screen blacked out

Theo Band theo.band at xanadu-wireless.com
Thu Mar 8 07:52:39 UTC 2007

techlists at comcast.net wrote:
> I have a CentOS 4.3 workstation I use for experimentation on my desk at work. It was plugged into an old LG 14" monitor, and I switched the video cable to a Samsung 17" LCD without rebooting.
> The screen resolution was set to 800x600 on the 14" monitor, and the display worked fine at 800x600 after switching to the Samsung 17". When I changed the resolution to 1024x764, the screen went black and I haven't been able to get it back again.
> I hoped rebooting and having the system search for new hardware would adjust the display driver to the correct monitor but it didn't. I booted with CD1 in rescue mode and changed /etc/inittab to start in command line mode (3), but the screen still goes black after going through some initial boot processes.
> I suspect the issue is driver related, rather than screen resolution related. When I initially went to change the resolution, it recognized the monitor as a generic VGA, and I changed the monitor type to Samsung Syncmaster 711T at the same time as changing the resolution.
> How can I get the system to recognize the new monitor?
It's perhaps the refresh rate capability of the LCD. Just change 
manually the line in /etc/X11/xorg.conf so that the VertRefresh and the 
HorizSync match your LCD. Before you try, you can also go through any 
other resolution set for X11 to see whether that works. Press CRTL-ALT-+ 
(NUM-PLUS). Of course you should also have a look at the X log file 

Section "Monitor"
    Identifier   "Monitor0"
    VendorName   "Monitor Vendor"
    ModelName    "Your Brand"
    DisplaySize  380    300
    HorizSync    30.0 - 83.0 <- change these
    VertRefresh  55.0 - 76.0 <- change these
    Option        "dpms"

Can you switch to a virtual console with CRTL-ALT-F1 for instance?


More information about the CentOS mailing list