diff options
| author | Len Brown <len.brown@intel.com> | 2011-01-18 20:48:27 -0500 |
|---|---|---|
| committer | Len Brown <len.brown@intel.com> | 2011-02-17 17:08:46 -0500 |
| commit | 14796fca2bd22acc73dd0887248d003b0f441d08 (patch) | |
| tree | 45281c00405077fe1a099d585588d2173ee90fea /arch/x86 | |
| parent | 100b33c8bd8a3235fd0b7948338d6cbb3db3c63d (diff) | |
intel_idle: disable NHM/WSM HW C-state auto-demotion
Hardware C-state auto-demotion is a mechanism where the HW overrides
the OS C-state request, instead demoting to a shallower state,
which is less expensive, but saves less power.
Modern Linux should generally get exactly the states it requests.
In particular, when a CPU is taken off-line, it must not be demoted, else
it can prevent the entire package from reaching deep C-states.
https://bugzilla.kernel.org/show_bug.cgi?id=25252
Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/include/asm/msr-index.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h index 4d0dfa0d998..b75eeab2b1e 100644 --- a/arch/x86/include/asm/msr-index.h +++ b/arch/x86/include/asm/msr-index.h @@ -36,6 +36,10 @@ #define MSR_IA32_PERFCTR1 0x000000c2 #define MSR_FSB_FREQ 0x000000cd +#define MSR_NHM_SNB_PKG_CST_CFG_CTL 0x000000e2 +#define NHM_C3_AUTO_DEMOTE (1UL << 25) +#define NHM_C1_AUTO_DEMOTE (1UL << 26) + #define MSR_MTRRcap 0x000000fe #define MSR_IA32_BBL_CR_CTL 0x00000119 |