On Mon, 23 Jun 2008, Zhao Yakui wrote:

On Fri, 2008-06-20 at 03:14 -0400, Len Brown wrote:

quoted

I notice on the T61 that this disables MWAIT for C2 and C3,
but not for C1.

While I know that the issue at hand is C2 and C3,
it seems misleading to boot with idle=nomwait
and see that MWAIT is used for C1.

What you said is correct. The description is not appropriate.Maybe the
following title will be appropriate.

 >Add boot option of "idle=nomwait" to disable mwait for CPU C2/C3

The boot option of "idle=nomwait" will disable mwait for CPU C2/C3 and
still use mwait for C1 if mwait is supported. 
In fact we only hope to disable mwait for CPU C2/C3 on some broken
system by adding this boot option.

How can I tell the system with 3 C-states to use all 3,
but not to use MWAIT for any of them?

idle=halt will not do, since it will delete C2 and C3 completely.
As I said, I think that "idle=nomwait" should do this.
If we have a parameter that disables MWAIT only for C2 and C3,
then it should not be called "idle=nomwait".

-Len