On 19 March 2014 06:23, Rafael J. Wysocki <r...@rjwysocki.net> wrote: > On Tuesday, March 18, 2014 12:25:14 PM Dirk Brandewie wrote: >> On 03/18/2014 12:08 PM, Srivatsa S. Bhat wrote: >> > On 03/18/2014 10:52 PM, dirk.brande...@gmail.com wrote: >> >> From: Dirk Brandewie <dirk.j.brande...@intel.com> >> >> >> > >> > I don't mean to nitpick, but generally its easier to deal with >> > patchsets if you post the subsequent versions in fresh email threads. >> > Otherwise it can get a bit muddled along with too many other email >> > discussions in the same thread :-( >> > >> >> Changes: >> >> v2->v3 >> >> Changed the calling of the ->stop() callback to be conditional on the >> >> core being the last core controlled by a given policy. >> >> >> > >> > Wait, why? I'm sorry if I am not catching up with the discussions on >> > this issue quickly enough, but I don't see why we should make it >> > conditional on _that_. I thought we agreed that we should make it >> > conditional in the sense that ->stop() should be invoked only for >> > ->setpolicy drivers, right? >> >> This was done at Viresh's suggestion since thought there might be value >> for ->target drivers. >> >> Any of the options work for me >> called only for set_policy scaling drivers > > And that's what we should do *today* in my opinion, unless we want to add > it to any ->target() drivers *right* now. Do we want that?
We don't have a platform right now that might want to use it, but people are doing this during suspend and so there is a high possibility that they will use it while normal cpu offline as well.. This is what I think: - We are adding a new callback to struct cpufreq_driver.. - We have a classic case here because a driver (set-policy ones) is both a driver and governor. And that's why its special.. - All we want here is to give drivers a chance to do something useful on the CPUs that are going down.. - There is nothing like GOV_STOP for setpolicy drivers as we never needed it and if we really want that, probably we better register setpolicy drivers as governors as well (only to a level where they would get GOV_START|STOP|etc) callbacks and nothing else. - And so I wanted the ->stop() callback to be more about the driver than the governor. - And because a policy contains only the CPUs that share clock line, its only required to call stop() for last CPU of the policy. -- viresh -- 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/
