Messages in this thread | | | Date | Sun, 22 Jan 2017 10:33:19 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH] x86 tsc: Add the Intel Denverton Processor to native_calibrate_tsc() |
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* Len Brown <lenb@kernel.org> wrote:
> 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:
Already upstream, as per:
695085b4bc76 x86/tsc: Add the Intel Denverton Processor to native_calibrate_tsc()
Thanks,
Ingo
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