amdgpu display corruption and hang on AMD A10-9620P

[Daniel Drake]

Hi,

We are working with new laptops that have the AMD Bristol Ridge
chipset with this SoC:

AMD A10-9620P RADEON R5, 10 COMPUTE CORES 4C+6G

I think this is the Bristol Ridge chipset.

During boot, the display becomes unusable at the point where the
amdgpu driver loads. You can see at least two horizontal lines of
garbage at this point. We have reproduced on 4.8, 4.10 and linus
master (early 4.12).

Photo: http://pasteboard.co/qrC9mh4p.jpg

Getting logs is tricky because the system appears to freeze at that point.

Is this a known issue? Anything we can do to help diagnosis?

Thanks
Daniel