All it does is open the card and close it again. If the card is speaking to the machine, that should reset it. If the card is really wedged it will not help, and a reset is in order. Here is an excerpt, as of January 7th, 1998. I omitted most stuff not specific to 3Dfx hardware.
Dedicated server requires no special permissions.
X11 has some garbage on the screen when 'loading'. This is normal in 16bit color mode. It would be very slow in any case. Some people are experiencing crashes with the GL renderer. Older versions of libMesa don't work properly.