From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vaidyanathan Srinivasan Subject: Re: [RFC PATCH V4 5/5] cpuidle: cpuidle driver for apm Date: Fri, 25 Mar 2011 23:31:57 +0530 Message-ID: <20110325180156.GC19214@dirshya.in.ibm.com> References: <20110322123208.28725.30945.stgit@tringupt.in.ibm.com> <20110322123336.28725.29810.stgit@tringupt.in.ibm.com> <20110323121458.ec7cdaf9.sfr@canb.auug.org.au> <4D89CA7D.8080108@linux.vnet.ibm.com> <4D8B550D.5000409@linux.vnet.ibm.com> Reply-To: svaidy@linux.vnet.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Len Brown Cc: Trinabh Gupta , arjan@linux.intel.com, Stephen Rothwell , peterz@infradead.org, suresh.b.siddha@intel.com, benh@kernel.crashing.org, venki@google.com, ak@linux.intel.com, linux-kernel@vger.kernel.org, xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org * Len Brown [2011-03-25 03:24:24]: > > > Maybe there is some other way to handle asymmetry ?? > > When somebody invents a system that needs asymmetry on purpose, > that is the time to get fancy. Until that day, simply print a > FW_BUG WARNING and fall back to default_idle(). We may print a warning but not switch to default_idle(). There could be laptops that gets an extra C-State when run on battery. So when the ACPI _PPC event happens for the C-State change, we need to handle the situation such that the states are refreshed for all CPUs in one step. Basically while we are updating the new C-State, the framework should not detect this as asymmetric and switch to default_idle(). Please fell free to suggest a more elegant solution to handle the runtime C-State change event, though symmetric across all CPUs. --Vaidy