Paul W. Abrahams wrote:

On Saturday 19 March 2005 1:27 pm, Carl E. Hartung wrote:

...

First, boot to run level 3 (no X.) I do this by just hitting the number "3"

key in grub before booting into SuSE.

...

Then log in as root and run "yast" to launch YaST2 in ncurses (text-based)

mode.

OK, that did it. Now I'm at the next problem (groan).

I can now get a legible screen. The problem with it is that it has a visual effect that I can best describe as a darker horizontal region that moves down the screen several times a second. I've been trying to find a monitor setting that eliminate that effect, with no success. The one that logically should do it -- Dell laptop @1024 -- does not do it. I've also tried the LCD monitor settings, and they are no better.

This sounds like it might be a beat frequency, which is caused by interference between two periodic signals having approximately the same frequency. In this case, one of the signals is the refresh (vertical) frequency of the monitor, while the other could be almost anything -- I have seen fluorescent lights interfere with a monitor set to refresh at approximately the same frequency as the electric company provides. Do you get the same effect when the room lights are off? In sax2, once you have set the screen resolution, try setting the vertical frequency at a few different settings. I'd suggest trying 56, 60, 72 and 75 Hz for starters. The horizontal sweep rate shouldn't need changing. Make sure to test each before saving, and remember that you can always back out of the test with a keypress. Don't get carried away with too high a setting, however, as you can damage a monitor by setting its sweep frequencies outside specifications. Most modern monitors should be able to handle a vertical sweep up to at least 80 Hz, perhaps as high as 120 for some modes. Just keep the rate reasonably low until you find something that works.

Paul & Paul, On Sunday 20 March 2005 04:51, Paul Hewlett wrote:

On Saturday 19 March 2005 21:46, Darryl Gregorash wrote:

...

Paul W. Abrahams wrote:

...

On Saturday 19 March 2005 1:27 pm, Carl E. Hartung wrote:

...

First, boot to run level 3 (no X.) I do this by just hitting the number "3"

key in grub before booting into SuSE.

...

Then log in as root and run "yast" to launch YaST2 in ncurses (text-based)

mode.

OK, that did it. Now I'm at the next problem (groan).

I can now get a legible screen. The problem with it is that it has a visual effect that I can best describe as a darker horizontal region that moves down the screen several times a second. I've been trying to find a monitor setting that eliminate that effect, with no success. The one that logically should do it -- Dell laptop @1024 -- does not do it. I've also tried the LCD monitor settings, and they are no better.

I have seen that effect when 2 monitors are physically close together. Is your laptop next to your desktop PC monitor ?

Quite likely you're right, judging from the description of the symptom. It comes from the magnetic fields of the vertical sweeps. The rate of ripples comes from the difference between their vertical sweep frequency and is just like a beat between to close but not identical musical notes. In those rare instances in the past when I've been able to work with a multi-monitor setup, I've found that orienting the screens at a relative angle--as close to 90 degrees as feasible--cuts down on the interference between the two monitors considerably. However, this phenomenon only occur between two CRTs, not between a CRT and an LCD. If there's only one CRT, then the interfering magnetic fields must be coming from something else. One possibility is a transformer, but it's unlikely it's a power supply, since that would represent a very poorly designed transformer that's wasting a lot of engergy by failing to contain the magnetic fields within its core. Paul A., what other electrical equipment is in the area of the monitor exhibiting those symptoms?

PaulH

Randall Schulz

On Saturday 19 March 2005 02:01 pm, Paul W. Abrahams wrote: <snip>

A complication in dealing with this is that as far as I can determine Dell provides no specs on its screen.

Did you provide a model number for that laptop already? Sorry, but I trashed your original post after replying. A manufacturing date and/or S/N would be helpful, too. I'm sure the specs you need are out there, you just have to know how to dig them up. Also, I wouldn't drive that display too long with the effect you're describing. It's more likely they're due to an inherent incompatibility between the display and the signals being sent to it than any kind of harmonic interference. This is especially true if it doesn't go away when you change modes. I'd attach an external (analog) VGA monitor until we can determine you've defined the graphics adapter correctly. Fiddling around with the display settings doesn't do much good if you're not using the right driver and/or settings for the graphics chip, itself. - Carl -- _______________________________________________________________________ C. E. Hartung Business Development & Support Services http://www.cehartung.com/ carlh@cehartung.com Dover Foxcroft, Maine, USA Public Keys 68396713 & F8207216 Reg. Linux User #350527 http://counter.li.org/ ----->>>>>http://www.fsf.org/campaigns/supportlinuxbios.html <<<<<-----

On Saturday 19 March 2005 05:43 pm, Paul W. Abrahams wrote:

It's an Inspiron 1000, rev. A03, serial #18850470553. I couldn't find a date of manufacture on the case. I also checked what Windows thought the video chip was: SiS M650, with resolution 1024x768 (max). Linux says it's an SiS SIS 650, and has no entry among the SIS chips for M650, so I assume that SIS650 and M650 are the same. There are a whole lot of chip-specific parameters that can be set, too; possibly Windows knows how to set them and Linux doesn't, but I don't know how to get Windows to reveal its settings.

Hi Paul, Sorry for the delay, but I was out providing tech support to some exasperating family members. (Grrr.) SiS M650, eh? Here's a great site where you can do some reading: http://www.winischhofer.net/sisdri.shtml I won't be back until late tonight, again, so do what you can and I'll catch up with you then. regards, - Carl -- _______________________________________________________________________ C. E. Hartung Business Development & Support Services http://www.cehartung.com/ carlh@cehartung.com Dover Foxcroft, Maine, USA Public Keys 68396713 & F8207216 Reg. Linux User #350527 http://counter.li.org/ ----->>>>>http://www.fsf.org/campaigns/supportlinuxbios.html <<<<<-----

* Paul W. Abrahams [03-20-05 18:43]: ...

Meanwhile I discovered a very useful web page on the very topic I care about: Linux on Dell Inspiron 1000 (www.cdavies.org/inspiron1000.htm). He suggests using X-configure and adding two stanzas to the Monitor section of XF86Config:

HorizSync 31.5-48.5 VertRefresh 40-70

I don't know how to get that effect out of Yast or Sax2, however.

Perhaps using a test editor and editing /etc/X11/XF86Config ???? -- Patrick Shanahan Registered Linux User #207535 http://wahoo.no-ip.org @ http://counter.li.org HOG # US1244711 Photo Album: http://wahoo.no-ip.org/gallery

* Paul W. Abrahams [03-20-05 19:14]:

I thought of doing that, but that file contains a dire warning at its head that it should not be edited because Sax will get very jealous.

And ?? Just be *sure* to follow existing format. Sax2 is *not* the only user of XF86Config. Does it's jealousy extend to those other apps? -- Patrick Shanahan Registered Linux User #207535 http://wahoo.no-ip.org @ http://counter.li.org HOG # US1244711 Photo Album: http://wahoo.no-ip.org/gallery

* Paul W. Abrahams [03-20-05 20:27]:

In any event, I tried putting in the suggested parameters and not calling Sax2. Alas, it did not help.

And you restarted X, init 3, init 5 ? -- Patrick Shanahan Registered Linux User #207535 http://wahoo.no-ip.org @ http://counter.li.org HOG # US1244711 Photo Album: http://wahoo.no-ip.org/gallery

Paul W. Abrahams wrote:

At the moment I can't even run Sax2 because I'm back in the state where the screen fills with vertical lines. But I haven't tried sax2 -l yet, and that might help a little.

Boot to runlevel 3, log in as root, and run sax2 (no parameters) from the console. The screen will come up in a "suggested" video mode, which should be a standard SVGA mode.

using X-configure and adding two stanzas to the Monitor section of XF86Config:

HorizSync 31.5-48.5 VertRefresh 40-70

I don't know how to get that effect out of Yast or Sax2, however.

This is from memory: sax2 will come up with an expandable tree on the left. The top selection is monitor/video card configuration. Expand that tree. The frequency ranges can be entered in one of the tabs in the monitor configuration selection, which I believe is the first selection.