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authorLen Brown <len.brown@intel.com>2010-05-24 14:27:44 -0400
committerLen Brown <len.brown@intel.com>2010-05-28 13:58:57 -0400
commit02cf4f9808382af7265cafc33dc86ec5875526aa (patch)
tree6e4b7fc98a125e6af6011ee04e5fbf2d2fe38c4f /drivers/idle
parenta7d27c37533524e23bbdc9ba1d78e3241b7483ea (diff)
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ACPI: acpi_idle: touch TS_POLLING only in the non-MWAIT case
commit d306ebc28649b89877a22158fe0076f06cc46f60 (ACPI: Be in TS_POLLING state during mwait based C-state entry) fixed an important power & performance issue where ACPI c2 and c3 C-states were clearing TS_POLLING even when using MWAIT (ACPI_STATE_FFH). That bug had been causing us to receive redundant scheduling interrups when we had already been woken up by MONITOR/MWAIT. Following up on that... In the MWAIT case, we don't have to subsequently check need_resched(), as that c heck was there for the TS_POLLING-clearing case. Note that not only does the cpuidle calling function already check need_resched() before calling us, the low-level entry into monitor/mwait calls it twice -- guaranteeing that a write to the trigger address can not go un-noticed. Also, in this case, we don't have to set TS_POLLING when we wake, because we never cleared it. Signed-off-by: Len Brown <len.brown@intel.com> Acked-by: Venkatesh Pallipadi <venki@google.com>
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