On Fri, 28 May 2010, Chase Douglas wrote: > On Fri, 2010-05-28 at 00:16 -0400, Len Brown wrote: > > > I see that you have updated this code in your tree to disable C4 and C6 > > > on atom. This has piqued my curiosity. I've now seen 2 atom netbooks > > > from different OEMs that hide C4 when you plug the power in. After the > > > first machine I thought, "must be a BIOS/ACPI bug," but now I'm > > > beginning to wonder if there's some issue with atom C4 states? That's > > > beside the fact that I've not seen C6 on either machine at all. Do you > > > have any insight? > > > > The reasoning behind ACPI taking deep C-states away > > when on AC is the assumption that users on AC > > care more about low latency and high performance > > than they care about power savings, heat, and noise. > > Maybe they forgot that a netbook is still a *lap*top when they did this, > cause I can't keep mine on my lap when it's plugged in :). The CPU idles > at 60 centigrade when powered on, and drops to a manageable 30-ish > centigrade when running on battery. > > > So my intent is to give Linux control over this decision, > > via PM_QOS or otherwise. At the moment C4 is commented out > > because when i first tested it failed the lapic timer workaround. > > I am looking forward to testing out these changes on my netbook once > this issue get sorted out! Atom C4 works in the current driver in the git tree -- test it now! cheers, -Len _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
