Two display anomalies (one FIXED, one left open)
Bob Chiodini
rchiodin at bellsouth.net
Thu Sep 8 11:13:21 UTC 2005
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:
> >>>>> (1)
> >>>>> Video card: NVIDIA GeForce 2 MX (generic)
> >>>>> Monitor: Samsung SyncMaster 930B (flat panel)
> >>>>> Driver: nvidia (the commercial one), but it happens as well with nv.
> >>>>> Resolution: 1280x1024, 32-bit color or 16-bit color
> >>>>> Sypmtom: Monitor flickers as if it's synching at very low rate.
> >>>>> The monitor reports that it is syching at 75Hz, but I still see flicker.
> >
> > Strange, this morning, the monitor is perfect. Even the auto-adjust works
> > (forgot to mention that it was aligning the image too far left). And I
> > didn't touch anything.
> >
> > I'm almost afraid to try rebooting. But I'll keep the synch advice handy in
> > case I see a recurrence.
>
> Looks like this morning was just a case of the ambient light obscuring the
> flicker. It was back this afternoon, and setting the vertical refresh
> rate to a max of 60 Hz seems to cure it.
>
> Auto-adjust works if it's done after logging in. If I do it at the login
> screen, it might display anomalies.
>
> >
> > 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.
>
> 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.
Good luck with a new cable.
Bob...
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