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Clock synchronization not working using syscall adjtimex

Question asked by Frederic Jary on Nov 25, 2015
Latest reply on Nov 30, 2015 by igorpadykov

Hello,

 

 

I am trying to synchronize imx6 cpu clock with the one of a NTP server using NTP protocol. It seems to work using settimeofday (step mode), however I need to implement the slew mode feature (using adjtime) in order to avoid the clock to be suddenly changed. The kernel discipline is performed with the adjtimex syscall. Can someone confirm that this feature cannot work with imx6 hardware?

 

Analysing the source code, I understand the tick timer is used to make the cpu clock go faster or slower. I suppose the issue is because the clock_event_device is registered with the CLOCK_EVT_FEAT_ONESHOT feature instead of CLOCK_EVT_FEAT_PERIODIC in the tick timer driver (/arch/arm/mach-imx/time.c). The timer is operating in free-running mode.

 

imx6q SoC

kernel imx_3.10.17_1.0.0_ga

 

Thank you.

 

Frederic

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