Two display anomalies (one still open)

[Bob Chiodini]

On Fri, 2005-09-09 at 05:59 -0400, Matthew Saltzman wrote:
> On Thu, 8 Sep 2005, Bob Chiodini wrote:
> 
> > On Wed, 2005-09-07 at 20:16 -0400, Matthew Saltzman wrote:
> >> If you are following this thread, there are updates on both issues below.
> >>
> >> Thanks for your suggestions so far.  Keep 'em coming!
> >>
> >> On Wed, 7 Sep 2005, Matthew Saltzman wrote:
> >>
> >>> On Wed, 7 Sep 2005, Bob Chiodini wrote:
> >>>
> >>>> On Tue, 2005-09-06 at 23:01 -0400, Matthew Saltzman wrote:
> >>>>> On Tue, 6 Sep 2005, Bob Chiodini wrote:
> >>>>>
> >>>>>> On Tue, 2005-09-06 at 20:58 -0400, Matthew Saltzman wrote:
> >> [...]
> >>>
> >>> That leaves this one:
> >>>
> >>>>>>>
> >>>>>>> (2)
> >>>>>>> Video card: ATI Radeon Mobility 7500 in an IBM Thinkpad T41.
> >>>>>>> Driver: radeon
> >>>>>>> Kernel: kernel-2.6.12-1.1398_FC4
> >>>>>>> Kernel option: video=radeonfb
> >>>>>>> X: xorg-x11-6.8.2-37.FC4.45
> >>>>>>> Symptom: When I use the VGA-out jack to connect to an overhead projector
> >>>>>>> or external monitor, the projector image ripples slowly, as though (very
> >>>>>>> narrow) waves are passing over it.
> >>>>>>>
> >>>>>>> In FC3, this behavior varied with the kernel version.  In FC4, I need
> >>>>>>> this
> >>>>>>> kernel in order to get proper ACPI behavior, so I haven't tested much.
> >>>>>>> In
> >>>>>>> WinXP, the display is rock-solid.
> >>>
> >>> I'll check refresh rate in XP and Linux and test some cables and report back.
> >>
> >> Haven't tested yet, but I did find out that the vert. refresh rate in XP
> >> is 60Hz.  It appears from the logs to also be 60Hz in X, but I changed
> >> xorg.conf anyway.  That does not appear to affect the problem on my
> >> externa monitor.  I will check the projector with a brand new cable
> >> tomorrow.
> 
> Capping the vert refresh rate at 60Hz in xorg.conf had no effect.  In 
> fact, it looks like 60Hz was the rate even before that change.
> 
> Brand new, high quality video cable had no effect.
> 
> Still stuck.  Audience still dizzy.
> 
> >>
> >> Forgot to note that the problem occurs in a virtual console as well as in
> >> X.
> >>
> >
> > Matthew,
> >
> > The virtual terminal here is 720x400, 31.4 Khz horiz. and 70 Hz vert.  I
> > would have expected 640x480 @ 60Hz.  Try lowering the resolution in X.
> > That may not be ideal, but it may yield a clue.
> 
> I use the radeonfb module, so I'm not sure what the VC specs are.  How did 
> you get that info?
> 
> >
> > Good luck with a new cable.
> 
> Thanks.  Wish I had better news.
> 
> >
> >

Matthew,

Maybe you could have the audience shift side-to-side at the same rate as
the distortion ;-)  Seriously, sorry to hear no success.

I got the VT frequencies from the "info" menu item on my monitor.

What resolution are you using for X?

Does removing video=radeonfb from the kernel command line make any
difference?

You could also try the VESA driver in X.

Bob...