amdgpu hangs on boot or shutdown on AMD Raven Ridge CPU (Engineer Sample)

[Chris Chiu]

Hi,
    We are working with new laptops that have the AMD Ravenl Ridge
chipset with this `/proc/cpuinfo`
https://gist.github.com/mschiu77/b06dba574e89b9a30cf4c450eaec49bc

    With the latest kernel 4.15, there're lots of different
panics/oops during boot so no chance to get into X. It also happens
during shutdown. Then I tried to build kernel from
git://people.freedesktop.org/~agd5f/linux on branch
amd-staging-drm-next with head on commit "drm: Fix trailing semicolon"
and update the linux-firmware. Things seem to get better, only 1 oops
observed. Here's the oops
https://gist.github.com/mschiu77/1a68f27272b24775b2040acdb474cdd3.
However, I still get stuck on the following messages during boot very
often
""
[    4.998241] endless kernel: [drm] amdgpu kernel modesetting enabled.
[    4.998288] endless kernel: checking generic (e0000000 7f0000) vs
hw (e0000000 10000000)
[    4.998289] endless kernel: fb: switching to amdgpudrmfb from EFI VGA
""
I turned on drm.debug=0xe while booting, but no more information at this point.
Anything I can do at this point?

    And there's 1 more information may be helpful. Sometimes the
system boots OK with the blank screen, I can't switch to virtual
console, but it did respond to the magic sys-rq key. The dmesg with
drm.debug=0xe is here
https://gist.github.com/mschiu77/291e47b1f07dc52be9461c55c820464c.

    I'm pretty sure it's due to the amdgpu driver. Because when I boot
with my own kernel which disables the amdgpu driver, all these
symptoms went away. Please suggest anything I can do for this. Thanks

Chris