Constantly Running Tankless Toilet

I didn't see anything else out there...

I've had a running wallmount toilet for the last 2 hours. Jiggling the handle does not help. I have no ideas what to do. As the title indicates, there is no tank. It's a commercial style (don't know the proper terminology) toilet that has plumbing coming out of the wall. And the only known shutoff turns off the water for the entire building. The toilet bowl is fortunately not filling up, but there is a constant flow of water (rush of water is more appropriate).
Can I do something with the screws/nut to "reset" it? What can I do?

Any help is appreciated!
-T

Is it a chromed flush valve mounted above the toilet?
If so, the shutoff valve should be on the chromed anglestop that you see on the feed pipe before the actual flush valve...
Remove the anti-tamper cover on the end of the stop and you can use a standard screwdriver to shut the water off...
Once you do that, you can have a plumber come in to repair the valve - it is probably just a bad diaphragm or seal in the valve itself...

Perfect. Thank you.