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From: Paul on 14 May 2010 12:17
jw(a)eldorado.com wrote:
> On Thu, 13 May 2010 19:55:54 -0400, Paul <nospam(a)needed.com> wrote:
>
> Yeh, I have used this article in the past,
>> Apple makes an adapter for DVI computer to ADC monitor.
>>
>> http://www.amazon.com/Apple-M8661LL-Display-Adapter-4038234011420/dp/B00011KHT2/ref=tag_tdp_ptcn_edpp_url
>>
> This adapter seems to NOT have power either.

That is my mistake. I think the adapter turns out to be inside
the main "blob". The "blob" has pins for an AC power cord, so
the "blob" plugs into the wall.

>>
>> http://g-ecx.images-amazon.com/images/G/01/ciu/f8/bd/2f14810ae7a0c36c03fea110.L.jpg
>

> I agree, but it causes me to wonder if my video cards and their
> present drivers will support the Apple monitor. No point in spending
> money for an adapter if my present computers won't support the
> monitor.
>
> Thanks for your input.
>
> Duke
>> Paul

You can get virtually any resolution you want, within reason.
Powerstrip, from entechtaiwan.com can be used. Mainly, that
works with ATI or Nvidia based video cards (and is less likely
to work with things like the GPU inside a laptop). Also, the
ATI and Nvidia control panels, may have provisions for custom
resolution settings.

The horizontal, vertical, front porch, back porch, are all supposed
to be programmable in hardware. This may be more evident, when using
Linux to run the computer hardware. Frequently, people are able to
achieve different and more useful results, while using Linux to drive a
monitor.

In Windows, the limitation could be hard coded ones in the driver.
Some manufacturers of integrated GPUs, choose to not update
their drivers, to support new resolutions when needed. The
limitation may not be fixed by the hardware itself. It is
likely, that a couple hardware registers, hold the setting
for the number of pixels on horizontal and vertical.

A certain vintage of PC video cards, have out-of-spec DVI
outputs. The Wikipedia article on DVI, states what the
top resolution is for single link DVI. There are some
video cards, where the driver, on purpose, won't allow the
highest values to be used. It is because the hardware pad
drivers can't run fast enough, to support that resolution,
and the user would see "colored snow" if they allowed it.
Some cards may pass, some cards may fail. To "cover their tracks",
the drivers blocked the upper resolutions. And one driver writer
error, actually blocked a particular lower resolution value as
well, due to an arithmetic error. The vintage of card,
might be a DVI connector on something around the FX5200 era.
A couple of web sites tested this, using a Tektronix storage
scope and eye diagram software, to do pass-fail testing
of DVI outputs. Those sites have not done comparable
testing, in recent times (likely because all the cards
would pass, and they'd have no article to write).

For example, this card reaches 141MHz, short of the full 165MHz.
The orange signal, is not allowed to touch the three blue
compliance regions. Some cards only make it to 135MHz.

http://www.tomshardware.co.uk/the-tft-connection,review-1128-18.html

This page shows some "eye failures", where the signal touches the
dark blue regions. The eye diagram software loaded into the scope,
is supposed to automatically adjust for correct amplitude, so there
should be no need for manual adjustments while doing these tests.
(And that is to prevent operator error, from screwing up the
pass or fail.) I've run similar software at work, and it's loads
of fun (I wasn't doing DVI though). Other I/O standards also
have eye diagrams like that, that must be met.

http://www.tomshardware.co.uk/the-tft-connection,review-1128-11.html

So if a PC card lacks a certain resolution, it could be
the driver preventing you from seeing an out-of-spec output.
But equally well, it could just be lazy driver maintainers,
who don't want to support wide LCD screens, on old video
devices. If Powerstrip supports your hardware, that would be
the solution of last resort, after you've thoroughly checked
your video card drivers (and Googled for hacks to them).

Paul
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