Anyone have any idea what causes a serious display problem with Kali on a Macbook Pro 2015. The opening screen is half white, then when I login, the entire display is unusable. Interestingly, if I hold down control during the boot sequence, I do not get the problem. I currently have AMD ATI Venus XT Radeon HD 8870m

Kernel driver in use: radeon
kernel modules: radeon, amdgpu

Any insight into the problem would be beneficial.