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| author | Feng Tang <feng.tang@intel.com> | 2013-03-12 11:56:45 +0800 |
|---|---|---|
| committer | John Stultz <john.stultz@linaro.org> | 2013-03-15 16:50:26 -0700 |
| commit | c54fdbb2823d96b842d00c548e14dbc0dd37831d (patch) | |
| tree | 1193dec6db8b75b990c0375ac8a55bfd2ffc034c /arch/x86/kernel/cpu/intel.c | |
| parent | 3195ef59cb42cda3aeeb24a7fd2ba1b900c4a3cc (diff) | |
| download | op-kernel-dev-c54fdbb2823d96b842d00c548e14dbc0dd37831d.zip op-kernel-dev-c54fdbb2823d96b842d00c548e14dbc0dd37831d.tar.gz | |
x86: Add cpu capability flag X86_FEATURE_NONSTOP_TSC_S3
On some new Intel Atom processors (Penwell and Cloverview), there is
a feature that the TSC won't stop in S3 state, 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.tang@intel.com>
[jstultz: Fix checkpatch warning]
Signed-off-by: John Stultz <john.stultz@linaro.org>
Diffstat (limited to 'arch/x86/kernel/cpu/intel.c')
| -rw-r--r-- | arch/x86/kernel/cpu/intel.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c index 1905ce9..e7ae0d8 100644 --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -96,6 +96,18 @@ static void __cpuinit early_init_intel(struct cpuinfo_x86 *c) sched_clock_stable = 1; } + /* Penwell and Cloverview have the TSC which doesn't sleep on S3 */ + if (c->x86 == 6) { + switch (c->x86_model) { + case 0x27: /* Penwell */ + case 0x35: /* Cloverview */ + set_cpu_cap(c, X86_FEATURE_NONSTOP_TSC_S3); + break; + default: + break; + } + } + /* * There is a known erratum on Pentium III and Core Solo * and Core Duo CPUs. |
