[CentOS] XORG and LCD Projector

Sun Sep 11 14:25:13 UTC 2011
Robert Heller <heller at deepsoft.com>

At Sun, 11 Sep 2011 20:34:30 +0700 CentOS mailing list <centos at centos.org> wrote:

> 
> 
> 
> dear guys,
> 
> I have a problem between my CentOS 5.5 (on Axioo notebook) and LCD
> Projector. When I connect my notebook to LCD Projector, it can detect my
> notebook.

VGA or DVI?

> But when I press Fn + F7 to activate dual monitor between my notebook and
> LCD Projector it goes to blank screen. FYI, the LCD Projector is NEC but I
> don't know the series.

Which screen is blank? The notebook's or the LCD Projector or both?

> I've tried to change display using dual head monitor but it has no effects.

There are two different things going on here.

"dual head monitor" normally means that the two monitors display
*different* stuff.  This *usually* implies that the *video card*
specificly supports two independent monitors, usually by having two
frame buffers and two video outputs.  This usually also implies *two*
Device sections in xorg.conf, eg you (logically) have two video cards
installed (even if they are both on the same physical 'card' or even same
physical 'chip'). 

*Most* laptops/notebooks DON'T have "dual head monitor" capable video
cards.  What they have is a video output that goes to a logical "Y"
connection: *one* frame buffer+video output circuit, going to two video
connections, one being the internal LCD and the other being the VGA (or
DVI with newer laptops/notebooks) connector.

The Fn + F7 generally toggles between two or three states:

Video goes to the internal screen.
Video goes to the external screen.
Video goes to both screens (*some* laptops/notebooks can't do this, esp.
if the scan rates are incompatible).

In all cases there is only one video 'Device'.  The Fn + F7's logic is
like pluging in different monitors into the *one* video output
connection on a desktop.


> Do I need some driver??

Probably not.  It might be that you need to have different things in
your Screen section, partitularly in the Display SubSection.  It might
be that the LCD Projector cannot handle the display mode(s) specificed.
Is the LCD Projector displaying a message to the effect that an
unsupported sync rate or video mode in being used?

> 
> and this is my xorg configuration :
> Section "Device"
>         Identifier  "Videocard0"
>         Driver      "openchrome"
> EndSection
> 
> Section "Screen"
>         Identifier "Screen0"
>         Device     "Videocard0"
>         DefaultDepth     24
>         SubSection "Display"
>                 Viewport   0 0
>                 Depth     24
>                 Modes    "1280x800" "1024x768" "800x600" "640x480"
>         EndSubSection
> EndSection
> 
> Hope you guys can help me. Thanks.
> 
> 
> Andrew.
> 
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>                                  

-- 
Robert Heller             -- 978-544-6933 / heller at deepsoft.com
Deepwoods Software        -- http://www.deepsoft.com/
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