In an X Video Driver, what is the PROBE_TRYHARD flag used for in a call to a drivers Probe function?

While writing an X video driver, I was recently looking at xf86str.h, a standard Xorg header file, for the PROBE_ types, and noticed there was a third I had never heard of, namely PROBE_TRYHARD. Under what circumstances, if any, would an X server put that flag in a call to a driver's Probe function, and what would the Probe function 开发者_JAVA技巧be expected to do in response?

It seems to be totally unused, both in the X server and in all xf86-video DDXs (drivers).

According to an X developer, it "was probably meant for the bad old days when you had to smash ISA ports and guess"