Hi Rafael, Mark, On Sun, Feb 5, 2012 at 12:04 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote: > On Sunday, February 05, 2012, mark gross wrote: >> On Fri, Feb 03, 2012 at 03:04:43PM +0100, Pihet-XID, Jean wrote: >> > Looping in linux-pm >> > >> > On Fri, Feb 3, 2012 at 1:14 AM, Venkatesh Pallipadi <venki@xxxxxxxxxx> wrote: >> > > Looks like change "PM QoS: Move and rename the implementation files" >> > > made pm_qos depend on CONFIG_PM which depends on >> > > PM_SLEEP || PM_RUNTIME >> > > >> > > That breaks CPU C-states with kernels not having these CONFIGs, causing CPUs >> > > to spend time in Polling loop idle instead of going into deep C-states, >> > > consuming way way more power. This is with either acpi idle or intel idle >> > > enabled. >> > > >> > > Either CONFIG_PM should be enabled with any pm_qos users or >> > > the !CONFIG_PM pm_qos_request() should return sane defaults not to break >> > > the existing users. Here's is the patch for the latter option. >> > I think the real question is whether PM QoS should be functional in >> > all cases (as is ACPI) or whether only if certain options are set >> > (CONFIG_PM). >> > In the current code if CONFIG_PM is not enabled, a dummy PM QoS API is >> > provided as function stubs in order for the build to succeed. >> > >> > Rafael, Mark, >> > What do you think? Should PM QoS be enabled in all cases? Are there >> > any known dependencies with CONFIG_PM? >> >> Yes I do think pm_qos interfaces should be enabled all the time and be >> independent of CONFIG_PM. Also, I still am not a fan of the renaming >> patch but, as the argument for and against renaming cannot be based on >> quantifiable things I've chosen not to let it bother me. >> >> I think Venki's change is a band aid and we should fix it right by not >> having a dependency on config_pm for the interface to behave. >> >> I'll take a look at why there is now a dependency before I have more to >> say. > > In kernel/power/Makefile: > > obj-$(CONFIG_PM) += main.o qos.o > > I guess that explains things. :-) Initially I thought we should have a way of disabling the feature on some (minimal) kernels and so thought CONFIG_PM was the option to use. > It's quite easy to make qos.o be independent of CONFIG_PM, in which case the > code added by Venki can be removed, so patches welcome (for 3.4, though). I am working on it, more to come soon. > > Thanks, > Rafael Thanks, Jean > _______________________________________________ > linux-pm mailing list > linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx > https://lists.linuxfoundation.org/mailman/listinfo/linux-pm _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/linux-pm
