On Thursday, March 05, 2015 07:50:26 AM Li, Aubrey wrote: > On 2015/2/13 0:24, Rafael J. Wysocki wrote: > > On Thursday, February 12, 2015 02:26:43 PM Peter Zijlstra wrote: > >> > >> Why bother with enter_freeze() for any but the deepest state (C6 in this > >> case)? > > > > User space may disable the deepest one (and any of them in general) via > > sysfs > > and there's no good reason to ignore its choice in this particular case > > while > > we're honoring it otherwise. > > > > So the logic is basically "find the deepest one which isn't disabled" and > > setting the pointers costs us nothing really. > > > > If the user has chance to disable C6 via /sys, that means c6 works? > Shouldn't we ignore user space setting during freeze? Otherwise, we will > lost S0ix?
We can't ignore it, because we don't know the reason why the state was disabled. It may just not work reliably enough on the given platform. -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
