https://bugs.freedesktop.org/show_bug.cgi?id=94874
--- Comment #16 from Paulo Dias paulo.miguel.dias@gmail.com --- fixed in 4.6.0 rc5.
commit bfaddd9fc8ac048b99475f000dbef6f08297417f Author: Alex Deucher alexander.deucher@amd.com Date: Mon Apr 18 11:19:19 2016 -0400
Revert "drm/radeon: disable runtime pm on PX laptops without dGPU power control"
This reverts commit e64c952efb8e0c15ae82cec8e455ab4910690ef1.