Messages in this thread Patch in this message | | | From | Len Brown <> | Subject | [PATCH] x86 tsc: Add the Intel Denverton Processor to native_calibrate_tsc() | Date | Sat, 21 Jan 2017 02:52:38 -0500 |
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From: Len Brown <len.brown@intel.com>
The Intel Denverton microserver uses a 25 MHz TSC crystal, so we can derive its exact * TSC frequency using CPUID and some arithmetic, eg.
TSC: 1800 MHz (25000000 Hz * 216 / 3 / 1000000)
* 'exact' is only as good as the crystal, which should be +/- 20ppm
Signed-off-by: Len Brown <len.brown@intel.com> --- arch/x86/kernel/tsc.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index 46b2f41f8b05..b3e397a0f29d 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -694,6 +694,7 @@ unsigned long native_calibrate_tsc(void) crystal_khz = 24000; /* 24.0 MHz */ break; case INTEL_FAM6_SKYLAKE_X: + case INTEL_FAM6_ATOM_DENVERTON: crystal_khz = 25000; /* 25.0 MHz */ break; case INTEL_FAM6_ATOM_GOLDMONT: -- 2.11.0.161.g6610af872
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