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Subject[PATCH] x86: add the X86_FEATURE_NONSTOP_TSC_S3 cpu capability to new cpu
Date
New Intel Atom processors (Baytrail and Cherryview), have a TSC that 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.

Signed-off-by: Jeremy Compostella <jeremy.compostella@intel.com>
---
arch/x86/kernel/cpu/intel.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 1ef4562..8af195e 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -92,11 +92,16 @@ static void early_init_intel(struct cpuinfo_x86 *c)
set_sched_clock_stable();
}

- /* Penwell and Cloverview have the TSC which doesn't sleep on S3 */
+ /*
+ * Penwell, Cloverview, Valleyview and Cherryview have the TSC
+ * which doesn't sleep on S3.
+ */
if (c->x86 == 6) {
switch (c->x86_model) {
case 0x27: /* Penwell */
case 0x35: /* Cloverview */
+ case 0x37: /* Valleyview */
+ case 0x4C: /* Cherryview */
set_cpu_cap(c, X86_FEATURE_NONSTOP_TSC_S3);
break;
default:
--
1.9.1


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