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Diffstat (limited to 'arch/x86/kernel/cpu/intel.c')
-rw-r--r--arch/x86/kernel/cpu/intel.c18
1 files changed, 18 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 1edf5ba4fb2b..ed6086eedf1d 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -456,6 +456,24 @@ static void __cpuinit init_intel(struct cpuinfo_x86 *c)
if (cpu_has(c, X86_FEATURE_VMX))
detect_vmx_virtcap(c);
+
+ /*
+ * Initialize MSR_IA32_ENERGY_PERF_BIAS if BIOS did not.
+ * x86_energy_perf_policy(8) is available to change it at run-time
+ */
+ if (cpu_has(c, X86_FEATURE_EPB)) {
+ u64 epb;
+
+ rdmsrl(MSR_IA32_ENERGY_PERF_BIAS, epb);
+ if ((epb & 0xF) == ENERGY_PERF_BIAS_PERFORMANCE) {
+ printk_once(KERN_WARNING "ENERGY_PERF_BIAS:"
+ " Set to 'normal', was 'performance'\n"
+ "ENERGY_PERF_BIAS: View and update with"
+ " x86_energy_perf_policy(8)\n");
+ epb = (epb & ~0xF) | ENERGY_PERF_BIAS_NORMAL;
+ wrmsrl(MSR_IA32_ENERGY_PERF_BIAS, epb);
+ }
+ }
}
#ifdef CONFIG_X86_32