Want to get Radeon HD 8970M working with Debian 8.4 on MSI GX70 laptop

[Justin Belanger <justindbelanger@outlook.com>]

Hi,

I have a MSI GX70 laptop with Debian 8.4 on it. It has two graphics chips,
a Radeon HD 8970M and a Radeon HD 8650G. The CPU is a AMD A10-5750M.

I'd like to be able to use the Radeon HD 8970M, but right now, my laptop is
using software rendering (Gallium 0.4 on llvmpipe, according to the 
'glxinfo'
command).

When I boot the computer, I see the message "*ERROR* radeon kernel 
modesetting
for R600 or later requires firmware-linux-nonfree" twice (probably 
because of
the two graphics chips). So, I tried installing that 
firmware-linux-nonfree package.

After installing firmware-linux-nonfree, I see an error like "ring test 
0 failed"
when I turn the laptop on. The laptop waits for a few seconds, then reboots
itself, and then the error occurs again. I've fixed that error by 
booting in
recovery mode and removing the firmware-linux-nonfree package. But now I'm
back where I started.

Does anyone know why this "ring test 0 failed" error could be happening? Or
should I try a different approach to getting my 8970M chip to work?

Thanks!

- Justin