on 08/07/2012 19:49 Nate Lawson said the following:
> On Jul 8, 2012, at 2:11 AM, Andriy Gapon wrote:
> 
>> acpi_cpu.c has a block of code to write CST_CNT to SMI_CMD, but the block is
>> under #ifdef notyet.  It seems that the code was added that many years ago 
>> and
>> never enabled.
>> Now, judging from the reports I've seen on this mailing list, it appears that
>> _CST changes do happen and the driver seem to handle them sufficiently well.
>> I think that a lot of modern platforms do not even provide CST_CNT and assume
>> that an OS is able to handle C-state change notifications.
>> So, I guess that it should be safe to enable the code in question now.
>>
>> Could anyone with a FreeBSD laptop and non-zero CST_CNT in FADT please test 
>> this?
> 
> It was only under an #ifdef because at the time our CST implementation 
> couldn't handle CST changes cleanly. I had added some support for it, but 
> since it couldn't be tested, I wasn't sure how actual hardware would behave.
> 
> I think it's fine to enable now. I think 2007-era Thinkpads were some of the 
> first to add this feature.

Nate,

thank you for the information/explanation.

-- 
Andriy Gapon


_______________________________________________
[email protected] mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-acpi
To unsubscribe, send any mail to "[email protected]"

Reply via email to