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authorAndreas Herrmann <andreas.herrmann3@amd.com>2008-09-18 21:12:10 +0200
committerThomas Gleixner <tglx@linutronix.de>2008-09-23 11:38:53 +0200
commit09bfeea13cea843fb03eaa96b5d891fa0abdcc90 (patch)
tree83777d26c3029d373d67f61f6d08884ae275cea3
parenta8d6829044901a67732904be5f1eacdf8539604f (diff)
x86: c1e_idle: don't mark TSC unstable if CPU has invariant TSC
Impact: Functional TSC is marked unstable on AMD family 0x10 and 0x11 CPUs. This would be wrong because for those CPUs "invariant TSC" means: "The TSC counts at the same rate in all P-states, all C states, S0, or S1" (See "Processor BIOS and Kernel Developer's Guides" for those CPUs.) [ tglx: Changed C1E to AMD C1E in the printks to avoid confusion with Intel C1E ] Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
-rw-r--r--arch/x86/kernel/process.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index d8c2a299bfe..876e9189077 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -270,8 +270,9 @@ static void c1e_idle(void)
rdmsr(MSR_K8_INT_PENDING_MSG, lo, hi);
if (lo & K8_INTP_C1E_ACTIVE_MASK) {
c1e_detected = 1;
- mark_tsc_unstable("TSC halt in C1E");
- printk(KERN_INFO "System has C1E enabled\n");
+ if (!boot_cpu_has(X86_FEATURE_CONSTANT_TSC))
+ mark_tsc_unstable("TSC halt in AMD C1E");
+ printk(KERN_INFO "System has AMD C1E enabled\n");
set_cpu_cap(&boot_cpu_data, X86_FEATURE_AMDC1E);
}
}