On Mon, Jan 21, 2013 at 02:27:29AM -0500, Chen Gong wrote: > On Mon, Jan 21, 2013 at 02:38:41PM +0800, Feng Tang wrote: > > Date: Mon, 21 Jan 2013 14:38:41 +0800 > > From: Feng Tang <feng.t...@intel.com> > > To: Thomas Gleixner <t...@linutronix.de>, John Stultz > > <john.stu...@linaro.org>, Ingo Molnar <mi...@elte.hu>, "H. Peter Anvin" > > <h...@linux.intel.com>, x...@kernel.org, Len Brown <l...@kernel.org>, > > "Rafael J. Wysocki" <rafael.j.wyso...@intel.com>, > > linux-kernel@vger.kernel.org > > Cc: Feng Tang <feng.t...@intel.com> > > Subject: [RFC PATCH 1/5] x86: Add cpu capability flag > > X86_FEATURE_TSC_S3_NOTSTOP > > X-Mailer: git-send-email 1.7.9.5 > > > > On some new Intel Atom processors (Penwell and Cloverview), there is > > a feature that the TSC won't stop S3, say the TSC value won't be > > reset to 0 after resume. This feature makes TSC a more reliable > > clocksource and could benefit the timekeeping code during system > > suspend/resume cycle, so add a flag for it. > > > > Signed-off-by: Feng Tang <feng.t...@intel.com> > > --- > > arch/x86/include/asm/cpufeature.h | 1 + > > arch/x86/kernel/cpu/intel.c | 12 ++++++++++++ > > 2 files changed, 13 insertions(+) > > > > diff --git a/arch/x86/include/asm/cpufeature.h > > b/arch/x86/include/asm/cpufeature.h > > index 2d9075e..f7e1eac 100644 > > --- a/arch/x86/include/asm/cpufeature.h > > +++ b/arch/x86/include/asm/cpufeature.h > > @@ -100,6 +100,7 @@ > > #define X86_FEATURE_AMD_DCM (3*32+27) /* multi-node processor */ > > #define X86_FEATURE_APERFMPERF (3*32+28) /* APERFMPERF */ > > #define X86_FEATURE_EAGER_FPU (3*32+29) /* "eagerfpu" Non lazy FPU > > restore */ > > +#define X86_FEATURE_TSC_S3_NOTSTOP (3*32+30) /* TSC doesn't stop in S3 > > state */ > > > We have an existed "TSC always running in C3+" feature and name it as > X86_FEATURE_NONSTOP_TSC, so how about naming it with the same style, > like X86_FEATURE_NONSTOP_TSC_S3?
Yeah, actually I used a name X86_FEATURE_xxx_TSC, then I did a grep, and found there is no unified name convention for TSC, so I chose such a name. -------------- #grep _TSC arch/x86/include/asm/cpufeature.h #define X86_FEATURE_TSC (0*32+ 4) /* Time Stamp Counter */ #define X86_FEATURE_CONSTANT_TSC (3*32+ 8) /* TSC ticks at a constant rate */ #define X86_FEATURE_TSC_RELIABLE (3*32+23) /* TSC is known to be reliable */ #define X86_FEATURE_NONSTOP_TSC (3*32+24) /* TSC does not stop in C states */ #define X86_FEATURE_TSC_S3_NOTSTOP (3*32+30) /* TSC doesn't stop in S3 state */ #define X86_FEATURE_TSC_DEADLINE_TIMER (4*32+24) /* Tsc deadline timer */ #define X86_FEATURE_TSCRATEMSR (8*32+ 9) /* "tsc_scale" AMD TSC scaling support */ #define X86_FEATURE_TSC_ADJUST (9*32+ 1) /* TSC adjustment MSR 0x3b */ Thanks, Feng -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
