[geeks] Indy & LCD

[jodys at helluin.org]

On Mon, Nov 20, 2006 at 10:49:24AM -0500, Brooke Gravitt wrote:
> Anyone had luck booting an Indy with a Dell LCD (or any other, for
> that matter?) I have a 20" one that supports pretty wild configs, but
> can't get my Indy to boot with it attached. I don't have any tube
> monitors anymore to try. I have used this monitor on HPPA & SPARC
> boxen just fine.

The Indy graphics puts out sync on green, but it also puts out
composite sync and seperate horizantal/vertical sync. If I understand
correctly SGI 13w3 vertical sync maps to composite sync on a Sun 13w3.
It's possible that your LCD, seeing a signal on composite sync, is
deciding to use composite sync rather than sync on green (I have a
CRT that exhibits this behavior). Since the LCD doesn't actually get
a full composite sync signal, you get nothing.

Your LCD, per your later message, actually supports sync on green. If
you have a spare VGA cable, you can test this theory by snapping off
all of the sync pins. By doing this your insuring that the only sync
the LCD sees is the sync on green. Hopefully this will eliminate any
issues with the difference between Sun and SGI 13w3 adapter. If nothing
else, you can try removing *all* pins except RGB. I'm not positive,
but I believe that the Indy graphics after receiving no signal on the
sense pins will default to a simple 1024x768x60.  

Good luck, this stuff confused the hell out of me for quite some time.

Jody