Could it be a video driver issue stemming from a kernel update, I think.

You using the video driver for Intel, aren't you?

Might be the kernel update, but no, I'm using an ATI graphics card using amdgpu driver.

 Hardware Class: graphics card
 Model: "ATI VGA compatible controller"
 Vendor: pci 0x1002 "ATI Technologies Inc"
 Device: pci 0x743f  
 SubVendor: pci 0x1043 "ASUSTeK Computer Inc."
 SubDevice: pci 0x05d9  
 Revision: 0xc1
 Driver: "amdgpu"
 Driver Modules: "amdgpu"

Regards,

Oliver