Re: Problem using Cygwin, Dual Monitor, with External DVI

[Igor Pechtchanski <pechtcha at cs dot nyu dot edu>]

On Sun, 25 Sep 2005, Andy Glew wrote:

> I have a problem whereby X text does not render correctly, in a
> configuration involving dual monitors, an external DVI monitor in
> addition to the LCD monitor on my laptop. It renders in other
> configurations using these monitors and this laptop.
>
> I am using Cygwin/X [*] on an IBM ThinkPad T42p. The T42p is docked in
                      ^^^
Did you mean to include a footnote for this?

> an IBM 2878 docking station. The docking station is connected to an
> IBM ThinkVision monitor via a DVI cable.
>
> When I am in dual monitor mode (i.e. driving both monitors
> independently, with the external DVI monitor Windows' primary
> desktop), Cygwin/X applications such as xterm and GNU EMACS do not
> render on the external DVI monitor.  Their X windows (I am running
> Cygwin/X in multiwindow mode, so their X windows are also Windows
> windows) are blank - nothing displays.
>
> When I drag these windows over to the secondary monitor, the laptop's
> LCD display, they render.  Moreover, it is obvious that everything I
> typed while the window was on the external DVI monitor is now visible.
> Therefore, stuff is being added to X Windows' concept of what should
> be displayed on the window - it is just not getting sent to the
> screen.
>
> Similarly, when I drag the X windows back from the secondary, laptop,
> LCD, onto the external DVI monitor, the windows drag correctly. The
> old contents of the window display on the external DVI monitor, but
> nothing new gets drawn.
>
> ---
>
> However, when I am driving only the external DVI monitor, but not also
> driving the LCD at the same time, everything is drawn. That is how I
> am writing this message.
>
> ---
>
> Normally, at home I use Cygwin/X with an external analog video monitor
> in dual display mode with my laptop's LCD tablet.  This is one of the
> first times I habve used an external DVI monitor.
>
> ---
>
> Configuration info:
>
> Now, how can I tell what versions of Cygwind and Cygwin/X I am running?

Attaching the output of "uname -svr" and /tmp/XWin.log is usually enough
for most X problems.  For general Cygwin problems, it's best to attach the
output of "cygcheck -svr", as requested in the Cygwin problem reporting
guidelines at <http://cygwin.com/problems.html>.

> The external DVI monitor is reported by Window's device manager as a
> Plug and Play monitor, on an ATI Monility Fire GL T2.
>
> The laptop LCD panel is an IBM Thinkpad 1400 x 1050 LCD panel, also on
> ATI Monility Fire GL T2.

That said, let me take a guess: try using the -multiplemonitors option of
XWin, and see if it solves your problem.
	Igor
-- 
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     |,4-  ) )-,_. ,\ (  `'-'		Igor Pechtchanski, Ph.D.
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If there's any real truth it's that the entire multidimensional infinity
of the Universe is almost certainly being run by a bunch of maniacs. /DA

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