Hi All, On some new Intel Atom processors (Penwell and Cloverview), there is a feature that the TSC won't stop in 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 cycles.
The enabling efforts include adding new flags for this feature, modifying clocksource.c and timekeeping.c to support and utilizing it. The major change to timekeeping is the way to count suspened time, current way is trying to use the persistent clock first, and then try the rtc if persistent clock can't do it. This patch will change the trying order to: suspend-nonstop clocksource -> persistent clock -> rtc Please help to review them, thanks a lot! Changelog: v2: * Dump the code changing a clocksource's mult and shit, as suggested by John to not hurt accuracy * Modify the CPU feature flag name to be consistent with other flags * Solve the problem of judging S3/S4, as the clocksource counter will be reset after coming out S4. - Feng Feng Tang (4): x86: Add cpu capability flag X86_FEATURE_NONSTOP_TSC_S3 clocksource: Add new feature flag CLOCK_SOURCE_SUSPEND_NOTSTOP x86: tsc: Add support for new S3_NOTSTOP feature timekeeping: utilize the suspend-nonstop clocksource to count suspended time arch/x86/include/asm/cpufeature.h | 1 + arch/x86/kernel/cpu/intel.c | 12 ++++++++ arch/x86/kernel/tsc.c | 6 +++- include/linux/clocksource.h | 1 + kernel/time/timekeeping.c | 57 +++++++++++++++++++++++++++++++----- 5 files changed, 68 insertions(+), 9 deletions(-) -- 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/