Something odd with CPU frequency levels on AMD EE processors

[Jukka Ukkonen]

Hello all,

Previously my AMD EE CPUs have been reporting frequency levels all
the way down to 100 MHz and powerd also used those quite nicely.
Yesterday I noticed the fans running at much higher speed than what
has been normal on a mostly idle system. Now "sysctl dev.cpu.0"
shows me this...

dev.cpu.0.cx_usage: 100.00% last 622us
dev.cpu.0.cx_lowest: C8
dev.cpu.0.cx_supported: C1/1/0
dev.cpu.0.freq_levels: 1700/3870 1500/3461 1300/3105 1100/2720 800/2193
dev.cpu.0.freq: 800
dev.cpu.0.temperature: 34.6C
dev.cpu.0.%parent: acpi0
dev.cpu.0.%pnpinfo: _HID=none _UID=0
dev.cpu.0.%location: handle=\_PR_.P001
dev.cpu.0.%driver: cpu
dev.cpu.0.%desc: ACPI CPU

The system no longer sees the lower CPU frequency levels at all.
Obviously it will not try using them either.

This change must have been quite recent. Otherwise I would have
noticed the fans running at unusually high speeds much earlier
than yesterday evening. In any case now the idle system consumes
much more power than it really needs to producing only heat which
is exactly what I had tried to avoid when choosing the EE CPUs.

Here is the output from "uname -a" showing the OS version, the SVN
version number, and the time of the latest build.

FreeBSD sleipnir 10.2-STABLE FreeBSD 10.2-STABLE #0 r287529: Mon Sep  7
09:39:36 EEST 2015     root at sleipnir:/usr/obj/usr/src-10.2/sys/Sleipnir
 amd64

I hope someone has an idea what has happened. I would really like
to enable the lower frequency levels again as soon as possible.

--jau