Subject: Re: qtopia
To: Michael Lorenz <>
From: Steven M. Bellovin <>
List: tech-kern
Date: 06/03/2006 19:44:14
On Sat, 3 Jun 2006 19:35:02 -0400, Michael Lorenz <>

> >>> Except that some of us can't look at CRT displays with refresh rates
> >>> below 85Hz without seeing 'large area flicker' - which hurts.
> >> Then you should switch resolution as well.
> >> On a TFT that doesn't make much sense though and I think we should 
> >> have reasonable support for both cases.
> >
> > Well, if the monitor supports certain modes with >=85Hz vertrefresh, 
> > the display driver should as well (if the RAMDAC supports it, that 
> > is). On a sidenote, I have my two IIyama VMP454s running at 
> > 1600x1200x32 @ 100Hz without problem. As for TFTs, I was under the 
> > impression that the analog refresh rate doesn't matter because the 
> > internal analog->digital panel converter has no glow decay like a CRT 
> > (same goes for the refresh rate of a panel connected via DVI btw).
> The point was that it doesn't make sense to switch /resolution/ on a 
> TFT 
Actually, sometimes that is sane.  More precisely, on laptops with
external VGA connectors, you sometimes need to switch resolutions -- on
both the internal and external ports -- so that you can display on both
simultaneously.  I did that just yesterday (using xrandr) when giving a
talk -- my laptop is 1400x1050, but the projector preferred 1024x768.  It
looked *ugly* on my screen, but I could read it, as could the audience via
the projected image.

		--Steven M. Bellovin,