From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vaidyanathan Srinivasan Subject: Re: [RFC PATCH V4 3/5] cpuidle: default idle driver for x86 Date: Thu, 24 Mar 2011 22:02:20 +0530 Message-ID: <20110324163220.GB16408@dirshya.in.ibm.com> References: <20110322123208.28725.30945.stgit@tringupt.in.ibm.com> <20110322123244.28725.32435.stgit@tringupt.in.ibm.com> <4D89BDE2.9040606@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: <4D89BDE2.9040606@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org To: Trinabh Gupta Cc: Len Brown , arjan@linux.intel.com, peterz@infradead.org, suresh.b.siddha@intel.com, benh@kernel.crashing.org, venki@google.com, ak@linux.intel.com, linux-kernel@vger.kernel.org, sfr@canb.auug.org.au, xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org * Trinabh Gupta [2011-03-23 15:01:14]: > > On 03/23/2011 08:43 AM, Len Brown wrote: > >Why is this patch a step forward? > > Hi Len, > > I have basically moved the code for arch default and mwait > idle from arch/x86/kernel/process.c to a driver. This was > suggested by Venki (https://lkml.org/lkml/2010/10/19/460) > as part of pm_idle cleanup and direct call of > cpuidle_idle_call(). There is not much new code here. > > > > >>+obj-$(CONFIG_X86) += default_driver.o > > > >BTW, that's a pretty generic name for an x86 specific idle driver... > > > >I think that on builds that support intel_idle and acpi_idle, > >everything in this file will be unused, unless somebody uses some > >debugging cmdline params that should have been deleted ages ago. > > Yes, I agree that the name has to be x86 specific. I think the > routines would be used for pre-nehalem architectures that use > arch default or mwait. Mainly selection between default_idle (safe_halt), mwait_idle and c1e_idle needs to be placed in a default driver. This is the code that was 'outside' of cpuidle framework and directly used pm_idle(). This is mostly unused and overridden by intel_idle or acpi_idle, but still cannot be discarded. Maybe keep this as a module and probe/load only if both intel_idle and acpi_idle failed to load or excluded by command line or otherwise. --Vaidy