Two dvi connections can do two stripes of 1920 x 2400 @ 33 hz (which should be fine, movies refresh at what, 25 hz or so ?) or possibly 41 hz. This would seem to be ideal except you say the dcd cannot create resolutions higher than X_x_2048 ? Ka ka ka rap
Exceeding a height of 2048 results generates an error message:
Screen height 2400 is greater than 2048.000000 pixels. Decrease ActiveLinesPerFrame
which in turn leads to:
Compilation completed with errors. No video format created.
Looks like your lucky day tho (or maybe unlucky after we try a few), when the DCD definition file is included VFC ignores its own advice and creates a format anyway.
Four dvi inputs can do four 1920 x 1200 tiles or four 960 x 2400 stripes at 48 hz refresh. Bit that's a project for the distant future ...
That was schleusel's take on how a VPro/T221 should be configured (start here and read down a few posts): viewtopic.php?f=3&t=16719068&p=7284690&#p7284690
First, thank you.
You're welcome. Problem solving can be gratifying - if you actually solve anything. We see how this goes.
Second, you've gone where few men have gone before. Looking through all the threads here and googling like heck has not turned up anyone outside SGI who's been successful at creating dualling dcd formats. Woo-hoo
The solution was too obvious - once I found it. Logged five pages of trial-n-error/cause-n-effect notes before I had my doh! epiphany.
But third, try try again. 1920 x 1200 won't work on a T221. It wants 2400 in Y. Just for fun, I'm wondering if 2400 x 1920 is possible ?
Figuring out how to get VFC to include the DCD definition file was the first part of the puzzle. The second part will be providing the data needed by the DCD definition file. I used vfoinfo to explore all of the SGI-provided VPro 2@ fromats. In each case it appears SGI built the 2@ formats at half the target refresh rate, and half the target Y resolution:
./vfoinfo -q /usr/gfx/ucode/ODSY/vof/2@1024x768_60.vfo
/usr/gfx/ucode/ODSY/vof/2@1024x768_60.vfo 1024x384_29 ("1024 x 768 @ 60Hz for Odyssey Dual Channel Display")
./vfoinfo -q /usr/gfx/ucode/ODSY/vof/2@1280x1024_60.vfo
/usr/gfx/ucode/ODSY/vof/2@1280x1024_60.vfo 1280x512_29 ("1280 x 1024 @ 60Hz Dual Channel for Odyssey")
./vfoinfo -q /usr/gfx/ucode/ODSY/vof/2@1920x1200_60p.vfo
/usr/gfx/ucode/ODSY/vof/2@1920x1200_60p.vfo 1920x600_29 ("1920 x 1200 @ 60Hz Odyssey Dual Channel for SGI Flat Panel")
I followed that lead and created a 2@1920x2400_20uvf format. The 20Hz refresh rate comes from the T221 modeline SGI provides for the Onyx4 UltimateVision (look in section for "1/2 screen 3840x2400"): http://techpubs.sgi.com/library/tpl/cgi ... 137-PARENT
I chose 20Hz to keep the pixel clock as low as possible - even at that the pixel clock needed for two displays at 1920x2400 may be be too high unless that situation is helped by the DCD circuitry. In the same thread linked above schleusel mentions the (single?) DVI port on a V12 tops out at 165Mhz. The combined pixel clock of the attached 2@ format is 197.777MHz (for both DVI ports on the DCD).
vfoinfo for the resulting format follows that of the SGI-generated 2@ formats:
./vfoinfo -q 2@1920x2400_20uvf.vfo
2@1920x2400_20uvf.vfo 1920x1200_10 ("2@1920x2400_20uvf")
- we'll have to see what effect, if any, ignoring the screen height error has on the compiled format.