Created attachment 90948 [details]
This patch implements the FreeBSD version of drmCheckModesettingSupported().
It was written by Konstantin Belousov, and obtained from:
to which I added a pair of minor adjustments in order to support GNU/kFreeBSD as well.
It is known to correctly yield both positive and negative results with the i915kms and radeonkms drivers in kernel of FreeBSD.
Please send the patch to the dri-devel mailing list and ask somebody to commit it for you.
Okay, I'm closing this bug.