C3+ states not correctly detected?

[Andy22]

Hi,

just wondering if there is anything i can do to get the higher C states correctly supported/reported?
I have "Report C3/5/6/7 to OS" enabled in the bios, but i only get:

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sysctl dev.cpu | grep cx

dev.cpu.0.cx_supported: C1/1/1 C2/2/80
dev.cpu.0.cx_lowest: C2
dev.cpu.1.cx_supported: C1/1/1 C2/2/80
dev.cpu.1.cx_lowest: C2

thx
Andy

[chrisf4lc0n]

Does your CPU support deeper C states?
BIOS may do, but my CPU which is Celeron G1610 only supports down to C3 state. Anyway anything below C5 may cause problems with your PSU...

[Andy22]

Does your CPU support deeper C states?
BIOS may do, but my CPU which is Celeron G1610 only supports down to C3 state. Anyway anything below C5 may cause problems with your PSU...

Kinda hard to reasearch, since Intel in its matrix justs lists "idle state" supported.
Its a 1007U http://ark.intel.com/products/72061/Int ... e-1_50-GHz and belongs to the "3rd generation Intel® Core™ processor family" and going by the specs documentations it supports up to C7, which is also what my bios lists as max.

thx
Andy

[HansFranz]

Hi,

as far as I know c7 is supportet with Haswell (Generation 4) CPUs.
Nevertheless the problem reported here exists with my system too.
CPU: Intel Core i5 4570T
MB: Fujitsu D3222
The system fully supports C-states down to c7. This is working in Windows as well as in Ubuntu (14.04 LTS).
But in FreeNAS/NAS4Free the lowest detected C-State is c2.

B.t.w., could anybody explain how to interpret the aoutpu of sysctl?:
dev.cpu.0.cx_supported: C1/1/1 C2/2/80
C1: obviously the c-state but the "/1/1"
Same question for C2 etc.

Thanks and regards,
HF

[Eliminateur]

Well i was about to open a similar thread but it's better to leave it like it is.
my CPU( a P4 651, cedar mill) is reporting:

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dev.cpu.0.cx_supported: C1/1/20
dev.cpu.0.cx_lowest: C1

now, after doing some googling i found an interesting page in the freebsd wiki: https://wiki.freebsd.org/TuningPowerConsumption
there it says

Use of C2 state can be enabled by adding to /etc/rc.conf:
performance_cx_lowest="Cmax"
economy_cx_lowest="Cmax"

now i haven't been able to find ANY other website referencing "Cmax", all i've seen is directly referencing Cx (where X is the number you want).

I've set it on my box and now the lowest shown is C8 but the supported stays in C1 and i have seen no difference(turning to back to default now)

[fumantsu]

I had also the same thing. I force to have C4 (Avaton) but the supported is only until C2. Maybe is something with the kernel modules(?)

[chrisf4lc0n]

I think it varies widely... It seems to depend on the specific configuration you are running at the time.
For me it seems to be working "out of the box" and I can achieve C3 states on both cores without any additional setup.
I would however try Eliminateur's solution and add 2 lines to /etc/rc.conf

[Eliminateur]

on my setup it did nothing, CPU kept showing only C1.
in fact i changed my cpu to a C2D E4600 and it still shows only C1

[fumantsu]

I think it varies widely... It seems to depend on the specific configuration you are running at the time.
For me it seems to be working "out of the box" and I can achieve C3 states on both cores without any additional setup.
I would however try Eliminateur's solution and add 2 lines to /etc/rc.conf

You had as "supported" C3 states?

[chrisf4lc0n]

You had as "supported" C3 states?

Yup G1610 running in C3 states with no problems whatsoever!

[fumantsu]

So what I can imagine is that the kernel or some other package is not "updated" to support newer CPU models.