I wanted to toss in that I am also experiencing frequent freezing of my monitor using DisplayLink 2.4. I have a monitor connected to my 2011 MBP running Yosemite via a minideck 3.0, and after about 5 minutes of use or so it is freezing. Similarly to the OP, if I unplug until the windows reset, and plug it back in, it goes back to normal. This is making that monitor pretty much unusable.