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QNX Power modes using sysmgr_cpumode() API

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QNX Power modes using sysmgr_cpumode() API

Postby Anant Pai » Mon Apr 17, 2017 10:54 am

Hi All,

We are working on Application using Power Mode provided by QNX 6.6 Power Management Framework on ARM CortexA7 based Board and for one of our
application we need to put the processor into sleep, standby etc., modes supported by QNX. So, here looking at QNX referral document we found that
sysmgr_cpumode(int mode) does the job for us. But, wanted to know more on this function i.e., specifically the mode value, what are these mode values to be passed
while calling the API. Are these mode values are defined in QNX Library. If so, where? If not how can we handle CPU Modes using this function.

On reading more about this API, we understood that QNX Power Callout will be called by QNX Kernel when this API is called from User Space. Does QNX kernel
call Power Callout whenever sysmgr_cpumode API is called irrespective of the mode value or it depends on any specific mode values. Like,
MODE Value = GOTOSTANDBY -- Calls Power Callout which changes CPU Mode to Standby
MODE Value = GOTOIDLE -- Calls Power Callout which changes CPU Mode to IDLE and so on.

Can anyone help me in understanding the QNX Power Mode API’s.

FYI, The PMU unit is controlled by Cortex-M3 core and the A7 communicates with it via IPC.

Best Regards,

Anant Pai
Anant Pai
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