C-states on core-i7m

[Andreas Nilsson]

On Tue, Apr 20, 2010 at 5:56 PM, Andreas Nilsson <andrnils at gmail.com> wrote:

>
>
> On Mon, Apr 19, 2010 at 12:34 PM, John Baldwin <jhb at freebsd.org> wrote:
>
>> On Sunday 18 April 2010 4:52:33 am Andreas Nilsson wrote:
>> > Hello,
>> >
>> > my new laptop has a core-i7 620m and I expected it to have support for
>> > C3-state.
>> > sysctl dev.cpu.0
>> > dev.cpu.0.%desc: ACPI CPU
>> > dev.cpu.0.%driver: cpu
>> > dev.cpu.0.%location: handle=\_PR_.CPU0
>> > dev.cpu.0.%pnpinfo: _HID=none _UID=0
>> > dev.cpu.0.%parent: acpi0
>> > dev.cpu.0.freq: 149
>> > dev.cpu.0.freq_levels: 2667/25000 2533/23710 2399/22465 2266/21243
>> > 2133/20027 1999/18852 1866/17700 1733/16571 1599/15478 1466/14395
>> 1333/13334
>> > 1199/12297 1049/10759 899/9222 749/7685 599/6148 449/4611 299/3074
>> 149/1537
>> > dev.cpu.0.cx_supported: C1/3 C2/245
>> > dev.cpu.0.cx_lowest: C2
>> > dev.cpu.0.cx_usage: 100.00% 0.00% last 500us
>> >
>> > I've never seen it acutally use even C2. Are lower C-states not
>> supported
>> > yet for the core i7 cpus?
>>
>> I have used C3 on i7 CPUs.  I would check your BIOS options perhaps.  Note
>> that in the BIOS what shows up as "C3" to ACPI may be called "C6/C7".
>>
>> --
>> John Baldwin
>>
>
> Ok, thanks. I'll blame it on the bios then and hope that the next update
> fixes those issues :)
> I just hope that Lenovo ships an update soon.
>
> andrnils
>

Lenovo released a bios update, which I installed, but still no luck
recognizing more C-states or using anything but C1.

For a comparison I booted two other unices ( netbsd and ubuntu linux ), and
at least linux sees all c-states and uses C3 ( which I don't even see under
FreeBSD ). They both also managed to suspend (to ram ) and ubuntu even
resumed.

So there seems to actually be something awry with c-states on core-i7 on
fbsd :(

andrnils