https://bugs.freedesktop.org/show_bug.cgi?id=76490
--- Comment #12 from Gustavo Lopes mail@geleia.net --- I tried sprinkling si_dpm_ini() and si_dpm_enabled with printk and msleep statements, but while I can tell they're being executed (it takes much longer for the screen to become black due to the sleeps), I cannot see any log messages. The last lines I see are:
[drm] radeon kernel modesetting enabled. fb: switching to radeondrmfb from EFI VGA