Problems with syscall adjtimex on Android

[christianköstli]

we ported an open source implementation of ptp-v2 (http://code.google.com/p/ptpv2d/) to the android sabre-sd platform.

the same code runs good between two desktops or one desktop and a raspberry pi.

running on the sabre board we get very bad timing values:

- to adjust the clock in linux the program uses settimeofday to adjust big differences,

- and the syscall adjtimex, with modes ADJ_FREQUENCY to fine tune the frequency of the kernel clock (which we had to add to android libc).

we are no kernel experts and are wondering if adjtimex works as expected on this board/kernel.

do you have experience with ptp and or the clock behavior on the sabre-sd board in linux or android?

regards

christian

p.s.: we are using your android sdk 13.4

[daiane_angolini · Accepted solution]

I don´t know enough regarding ptp-v2 or adjtimex, but in my point of view, you cannot compare desktop or raspberry pi power management strategies with imx6 sabre sd.

It looks like adjtimex will change core clock/voltage in order to test something (or even get measurements), but you cannot set any clock value, as I know (you can choose between a range, or some values).

Could you, please, detail the clock behavior you´ve been expecting from imx6 sd?