linux/drivers/gpu/drm/amd/amdgpu: fix a random screen freeze issue which requires hard reset because of dpm for the Radeon RX 550
Maybe related: #17
Issue: The AMDGPU kernel driver crashes with the Radeon RX 550 videocard when launching intensive 3D tasks.
Thanks to diligent work from Pablo Estigarribia following the reports linked above, I was able to associate the crash with DPM (dynamic power management) functionality.
Then I came up with a temporary workaround in the form of https://gitlab.com/ranolfi/rforcedpm.
Anyway... both reports above are now marked as "fixed" although I tested with kernel 4.16.2 and issue is still present. Fix needed.
(TODO: test with amdgpu.dc=1) (though it shouldn't make a difference)
(TODO: test with kernel 4.16.3)
(TODO: report to kernel mailing list or bugzilla)