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Old 05-26-12, 07:03 PM   #6
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Join Date: Aug 2006
Posts: 16
Default Re: Black screen, suboptimal display with all my newer nVidia cards and SGI 1600SW

Here I am again after a few years.

In the meantime, I think that the display problems with the SGI 1600SW multilink adapter, and nVidia cards are due to some hardware incompatibililty along the DVI connection.

The older cards (GeForce GTS2, GeForce MX440) would show somewhat garbled displays in text mode, similar to what you would get on old CRT screens by mis-adjusting the H.POS potentiometer, until portions of the screen content would leave the display area on the left, and be "reflected", or appear mirrored, back into the display area from the left again. It would also appear as if upscaling to the full screen height would interleave black lines with those with actual content; and text and background colours could also be changed - depending upon actual screen content.

But these older cards would work perfectly - always - after the graphic driver for Windows or X11 (until X.Org ABI 10) started up.

Never cards, like the GeForce 8600 GT / 7600 GT? for which I originally reported the issue, would often produce *no visible display output* at all (i.e. a totally black display, though synced and backlights lit), and this both in text mode (after power on), or in graphics mode, with the suitable drivers.

In Linux, I could alleviate the problem by repeatedly switching between virtual text consoles and the X11 graphic display, until the image would finally appear. In Windows, it could often need many attempts to start the system, or (blindfoldedly) bring up a text cmd window, to full screen, and back to the graphic display, to get the same thing. And on both systems, changing the configuration, i.e. from a single screen to a twin view configuration, or resolutions, might result in a black screen (more often than not, actually).

The interesting thing is: This has not been problem of the 8600 GT / 7600 GT? card alone - but of all nvidia cards I have had ever since. Including this laptop here, which is a Quadro FX2500 or the like.

So I think that at some point in time, nVidia changed their DVI interface protocol (?) to become less suitable for the SGI multilink adapter, and they maintained the change ever since.

The problem does NOT occur on another younger DVI screen - I don't want to look up details on DVI to understand the problem any better; but I'd like if anyone from nVidia support could comment on the issue, and - maybe - design a better solution (regarding the use of older displays, or just the SGI multilink) for future adapters, if possible.

Yes, these things are old. But I have a few of them, they have better grayscale resolution than several more modern (cheaper) ones I own, and I just still like to use them. And, after all - the issue is a little engineering puzzle. I don't like it when things don't work which could.

Kind regards, Joerg
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