Oh wow, I didn't even realize that was who wrote this article. One time I was debugging an insane USB issue and diving deep into the usb stack of the kernel (it turned out it was a hw bug, but that's another story) and out of desperation emailed the usb kernel mailing list for tips, and GKH responded to me.
Anyone who is deeply knowledgeable about USB automatically has serious cred in my book. That rabbit hole just about killed me.
Here's an AMA GKH did a while back if you want to get to know him better: https://www.reddit.com/r/linux/comments/2ny1lz/im_greg_kroah...