On Monday, May 12, 2014 04:52:22 PM Daniel Lezcano wrote: > On 05/12/2014 04:19 PM, Li, Aubrey wrote: > > On 2014/5/12 22:08, Daniel Lezcano wrote: > >> On 05/05/2014 12:51 AM, Rafael J. Wysocki wrote: > >>> From: Rafael J. Wysocki <rafael.j.wyso...@intel.com> > >>> > >>> If freeze_enter() is called, we want to bypass the current cpuidle > >>> governor and always use the deepest available (that is, not disabled) > >>> C-state, because we want to save as much energy as reasonably possible > >>> then and runtime latency constraints don't matter at that point, since > >>> the system is in a sleep state anyway. > >>> > >>> Signed-off-by: Rafael J. Wysocki <rafael.j.wyso...@intel.com> > >>> --- > >>> > >>> This is on top of https://patchwork.kernel.org/patch/4071541/ . > >>> > >> > >> Wouldn't make sense to revisit play_dead instead ? > >> > > play_dead() is broken. > > > > Even if it works, we still should rely on cpuidle driver to place the > > CPUs into the deepest c-state, because there is no architectural way to > > enter deepest c-state and what play_dead() does is a bad assumption. > > Ok, let me rephrase it. Why not revisiting cpuidle_play_dead instead ?
Many drivers don't implement the ->enter_dead() callback. -- 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/
