Re: Ultra 5 TFT problems

x_at_x.x
Date: 12/10/03 

Date: Wed, 10 Dec 03 13:00:15 GMT

In article <3fd313a1$0$219$e4fe514c@news.xs4all.nl>, dick <dickdijk@xs4all.nl> wrote:
>x@x.x wrote:
>
>> In article <3fd01fec$0$206$e4fe514c@news.xs4all.nl>, ***
>> <dickdijk@xs4all.nl> wrote:
>>>Hi,
>>>
>>>I have an Ultra 5 that works OK with a Compaq 1520 TFT screen, but with a
>>>different TFT screen, Medion 6155, I only get a black screen. I even don't
>>>seen the system boot (black screen during OpenBoot)
>>>
>>>Are these TFT's so sensitive to correct input signals that the Compaq
>>>accepts it but the Medion not.
>>>
>>>Or could there be a different problem.
>>>
>>
>> Many resolutions that Sun uses on many of it's cards are composite sync,
>> and
>> not separate sync which PC commonly use. Some monitors handle both
>> and some only separate sync. You may be able to set a different
>> resolution in the fcode properties that has sep sync. 1280x1024x60 is
>> a
>> good first guess. Some older cards only have hardware for composite
>> sync, however, so it still may not be possible.
>
>How do I set the fcode properties? Do Solaris patches affect the OpenBoot
>program as well?

The fcode resolutions are burnt into the prom on the card, and can't
   be changed (for better or worse) without changing the prom.
So a Solaris patch might add/fix resolutions, but that would only
   take affect once Unix-X-CDE starts up.

Usually you change the fcode environment variable that redirects the output.
This is usually set to "screen" (I forget it's exact name).
You change it to something like "screen:r1280x1024x60", but unfortuanately
this is often slightly different for each card, so you'll have to find out
the exact format and list of res's for your card.

>>
>>>I read somewhere that the Sun video card (PGX, m64B@2, rev 4754.9a)
>>>outputs rather weak signals. Is this true and could that be the reason of
>>>the black screen?
>>>
>>
>> The "weaker" signal is the "PC" standard (2000 Ohms). Many of the cards
>> listed above are OEM's from PC vendors, and have the weaker signal, but
>> using
>> a PC monitor should match that. They just can't drive a "real" sun
>> monitor (75 Ohms) without a special "booster" cable.
>>
>>
>>
>>>Or could it have to do with the colordepth. The Ultra 5 is set to
>>>1024*768@60 and 8 bits color (quite low). This resolution is suppported in
>>>the Medion manual. In the manual it says "colordepth maximum 16 million,
>>>but could 8 bits be too low?
>>>
>>
>> Monitor just see the final RGB analog signals, they don't care how those
>> colors were derived.
>But I thought the TFT screens were digital!

Unless you are using DVI, it's still sent over the cable analog.
The monitor has to reconstruct the digital data, and figure out when to sample
  all the pixels so they line up with the "dots" on the LCD.
But even using DVI, any 8-bit stuff gets expanded to 24-bits
  internally before it goes to the DVI encoder (or DAC for analog).