> Date: Tue, 16 Dec 2014 21:34:29 -0800 > From: Philip Guenther <guent...@gmail.com> > > > R620 have similar settings and can't see C states in dmesg > > acpicpu0 at acpi0 > > That's either insane, or a bug in our acpicpu code, IMO.
Probably just the effect of the BIOS not advertising C states at all. Like you said, C1 support is mandatory, so there is no real need to advertise it unless some of the deeper states are advertised as well.