My two cents as a kernel developer, the driver is pretty abominable compared to the code quality of most of the rest of the kernel.
However, having a GPU driver not just be open source but in the upstream Linux kernel is a gigantic deal. Kernel development takes a long time, we have millions of lines in the amdgpu driver, and if every one of those dealt with the lengthy review process it would have never made it in the tree.
So it's a necessary evil. I do wish they would clean it up though, I sent a fix to amdgpu once that was the same thing for 3 different files that were largely duplicated. That kind of thing wouldn't fly anywhere else in the kernel
However, having a GPU driver not just be open source but in the upstream Linux kernel is a gigantic deal. Kernel development takes a long time, we have millions of lines in the amdgpu driver, and if every one of those dealt with the lengthy review process it would have never made it in the tree.
So it's a necessary evil. I do wish they would clean it up though, I sent a fix to amdgpu once that was the same thing for 3 different files that were largely duplicated. That kind of thing wouldn't fly anywhere else in the kernel