Using master of Poky git, accidentally putting the wrong version in a PREFERRED_VERSION field gets you this: 'NOTE: preferred version git of mesa-dri not available (for item mesa-dri) NOTE: versions of mesa-dri available: 2:8.0.4 2:9.1.0+git3+60e610e0426d79fc9080df1a9ae0a6be39af1380' Unfortunately, correcting your PREFERRED_VERSION to be '2:9.1.0+git%' fails with exactly the same message; for some reason you have to strip the epoch from PREFERRED_VERSION. It'd be nice if PREFERRED_VERSION respected the epoch, or if the version-mismatch error message removed the epoch.
All the code was there to support this but there was a small bug. Its fixed in: http://git.yoctoproject.org/cgit.cgi/poky/commit/?id=2f9328ff32cdbd67ba56a13a3a9a32820605a31f