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. :-) 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). Thanks, Rafael _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/linux-pm
