[ntp:questions] How do I enable PLL in the Linux kernel?
David L. Mills
mills at udel.edu
Wed May 28 19:17:19 UTC 2008
Anton,
See rfc2783 and header file timex.h.
Dave
Anton Persson A wrote:
> Hi,
>
> the manual for the ntpdc program says the following about the "kerninfo"
> command:
>
> "Obtain and print kernel phase-lock loop operating parameters. This
> information
> is available only if the kernel has been specially modified for a
> precision
> timekeeping function."
>
> The output I get from kerninfo is the following:
>
> ntpdc> kern
> pll offset: 0 s
> pll frequency: 0.000 ppm
> maximum error: 0.414224 s
> estimated error: 1.6e-05 s
> status: 0040 unsync
> pll time constant: 4
> precision: 1e-06 s
> frequency tolerance: 512 ppm
>
> My questions are:
> * What does "0040 unsync" mean?
> * Does this inform me that my
> kernel has NOT been "specially modified for
> a precision timekeeping function."?
> * How do I make sure the PLL is enabled?
> * Does the PLL feature require special hardware?
>
> Best regards,
> Anton Persson, Ericsson Sweden.
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