From 32c7553f824d0d76771404f0e11d6059f82e8de7 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Wed, 30 Jan 2008 13:32:41 +0100 Subject: [PATCH] x86: remove explicit C3 TSC check on 64bit Trust the ACPI code to disable TSC instead when C3 is used. AMD Fam10h does not disable TSC in any C states so the check was incorrect there anyways after the change to handle this like Intel on AMD too. This allows to use the TSC when C3 is disabled in software (acpi.max_c_state=2), but the BIOS supports it anyways. Match i386 behaviour. Cc: lenb@kernel.org Signed-off-by: Andi Kleen Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- arch/x86/kernel/tsc_64.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-) diff --git a/arch/x86/kernel/tsc_64.c b/arch/x86/kernel/tsc_64.c index 322b38c68198..c62f3b6eacc0 100644 --- a/arch/x86/kernel/tsc_64.c +++ b/arch/x86/kernel/tsc_64.c @@ -273,15 +273,8 @@ __cpuinit int unsynchronized_tsc(void) return 1; #endif - if (boot_cpu_has(X86_FEATURE_CONSTANT_TSC)) { -#ifdef CONFIG_ACPI - /* But TSC doesn't tick in C3 so don't use it there */ - if (acpi_gbl_FADT.header.length > 0 && - acpi_gbl_FADT.C3latency < 1000) - return 1; -#endif + if (boot_cpu_has(X86_FEATURE_CONSTANT_TSC)) return 0; - } /* Assume multi socket systems are not synchronized */ return num_present_cpus() > 1; -- 2.20.1