Most readers are only going to recognize the name Synaptics if they have had to go digging around in their laptop’s driver options, to fix a rogue trackpad issue. After all, the human-machine interface (HMI) specialist has very little reason to crop up in video discussions. But this week, Synaptics has acquired DisplayLink for $305 million cash, specifically for the firm’s video compression technology. This is the second deal this month for Synaptics, which also bought Broadcom’s wireless IoT assets for $250 million. That one is decidedly less up Faultline’s street, but DisplayLink is intriguing. Synaptics cites the growing demand for casting video between devices as a driver, and so it has whipped out its wallet. DisplayLink designs chips and…