On Saturday, December 01, 2007 6:27 AM, tesla-dev-bounces at opensolaris.org wrote:
> Mark Haywood wrote: >> Eric Saxe wrote: >> >>> Eric Saxe wrote: >>> >>>> Li, Aubrey wrote: >>>> >>>>> C-state driver will let the processor go into deeper c-state. >>>>> >>>>> >>>> I was thinking would use the existing mwait code path to bring the >>>> processor into the deeper c-states? >>>> ...or are you suggesting that the c-state driver would contain >>>> code that is invoked out of that path? >>>> >>>> >>> Sorry. In case you can't parse the above, let me try again. ;) >>> >>> I was thinking we would use the existing mwait code path to bring >>> the processor into the deeper c-states. >>> Are you suggesting that the c-state driver would contain the code >>> that could be invoked out of that path?... >>> or something else? >>> >> I was wondering what we were going to do here too. Do the deeper >> c-states tend to be vendor specific mechanisms? If so, then I think >> we might want this support in a separate driver that can be accessed >> via something like layered ioctls? This is what I was thinking of >> doing with the reworked p-state support. >> >> > Is your question referring to cpu vendors or BIOS/platform vendors? > Only Intel supports deeper c-states via mwait. Here, we can't use mwait to make the processor into deeper c-states. Instead, we must use the P_LVL2 command register or _CST object exported by ACPI table from BIOS. Thanks, -Aubrey
