RE: Root window shimmers with new nVidia graphic card

[<GChampoux at williams-int dot com>]

Harold,

You must be a mind reader (but, you already knew that).

That's exactly the situation.
The 980XGL has DVI output, which I had connected to a VGA cable with an
adaptor.
However, my LCD monitor has a DVI as well as VGA!
Why wasn't I using it in the first place? Duh?
I switched to a DVI cable and all is well.

Thanks a bunch!

Gerry

-----Original Message-----
From: cygwin-xfree-owner@cygwin.com
[mailto:cygwin-xfree-owner@cygwin.com] On Behalf Of Harold L Hunt II
Sent: Wednesday, April 14, 2004 12:33 PM
To: cygwin-xfree@cygwin.com
Subject: Re: Root window shimmers with new nVidia graphic card



Yup, it has nothing to do with Cygwin/X.

I wish you would have told us more about your monitor.  Is it an LCD
panel connected via a VGA (standard video for computers) cable, or is it

something else?  This problem occurs in the circuitry or cabling when
you use certain combinations of video cards and monitors over VGA
cables.  For example, I have five old video cards and a 19" 1280x1024
LCD panel; if I run it with four of the five video cards over VGA cables

I get the shimmering you speak of, while the fifth video card does not
cause the problem.  Oddly enough, the one that does not cause the
problem is one of my oldest video cards.

You will almost always be able to notice a very small amount of that
shimmering affect with any video card over VGA cables, but you'll have
to look very closely to be able to see it sometimes.  This problem
doesn't usually occur when using CRT monitors and I believe this is
because the shimmering is caused by a combination of the video card, VGA

cable, and the circuitry in the LCD panel that changes the analog VGA
signal back to a digital signal to drive the LCD; this conversion is a
lossy sort of process and it would make sense that small variations in
the incoming signal could get amplified during the conversion process
thus causing the shimmering.

So, if you have an LCD panel and you've got it hooked up with VGA
cables, then hope and pray that your LCD panel also has a DVI (digital
video interface, or whatever they have renamed it these days) connector.

  If it does, you're in luck though you may have to get a new video card

if your current one does not have a DVI output; if it doesn't, get used
to the shimmering or steal one of your co-workers hardware :)

Good luck,

Harold

GChampoux@williams-int.com wrote:
> I just got a replacement PC:
> HP xw4100 with nVidia Quadro4 980XGL graphic card.
> The previously PC was a Compaq DeskPro300 with an nVidia Quadro2 MXR.
>
> I re-installed cygwin as usual, and it operates properly.
> However, I've noticed something unusual in the display of the root
> window and scroll bars.
> They both "shimmer" as if the refresh rate was bad.
> Changing the refresh rate had no affect.
> All other windows (CygWin X or MS Windows) and their contents are
fine.
> If I use multi-window (integrated window manager - no root window) the
> scroll bars still shimmer/vibrate.
> If I use xdmcp, the problem is not present at all.
>
> It's only a nuisance, but I would like to address it.
> Maybe a driver setting?
> I'm using 52.16.
>
> CygWin version is 1.5.5.1.
> However, I did try the latest (1.5.9.1).
> Problem is unchanged.
>
> Any recommendations?

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