# Sometimes idle task receiving finite expected IDLE time. But all the task in portMAX\_DELAY

**URL:** <https://forums.freertos.org/t/sometimes-idle-task-receiving-finite-expected-idle-time-but-all-the-task-in-portmax-delay/13882>\
**Category:** Kernel\
**Tags:** tracealyzer, debug, tutorial, monitoring\
**Created:** [November 12, 2021, 12:04pm UTC](https://forums.freertos.org/t/sometimes-idle-task-receiving-finite-expected-idle-time-but-all-the-task-in-portmax-delay/13882 "2021-11-12T12:04:02Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![sivasuren90](https://avatars.discourse-cdn.com/v4/letter/s/c5a1d2/32.png) [@sivasuren90](https://forums.freertos.org/u/sivasuren90)\
**Post date:** [November 12, 2021, 12:04pm UTC](https://forums.freertos.org/t/sometimes-idle-task-receiving-finite-expected-idle-time-but-all-the-task-in-portmax-delay/13882/1 "2021-11-12T12:04:03Z")

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Hi,  
we are working on log power project using freertos. Whenever idle task call our application start to do power save process. System will exit only for interrupt.  
Most of time the nextTaskUnblokTime will be 0xFFFFFFFF while idle task call. But sometime nextTaskUnblokTime holding some finite number. its affecting our power save. But we are not running any timer in our app. Anybody have idea about it. I need to know Sometimes freeRTOS holding finite number in nextTaskUnblockTime.

Thank you.

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**Author:** ![rtel](https://d3iykfbgfh8zhg.cloudfront.net/user_avatar/forums.freertos.org/rtel/32/31_2.png) [@rtel](https://forums.freertos.org/u/rtel)\
**Post date:** [November 12, 2021, 6:40pm UTC](https://forums.freertos.org/t/sometimes-idle-task-receiving-finite-expected-idle-time-but-all-the-task-in-portmax-delay/13882/2 "2021-11-12T18:40:14Z")

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Are you using the tickless idle mode? If so the time to the next scheduled task execution is calculated by this function: [https://github.com/FreeRTOS/FreeRTOS-Kernel/blob/V10.4.5/tasks.c#L2159](https://github.com/FreeRTOS/FreeRTOS-Kernel/blob/V10.4.5/tasks.c#L2159)

Otherwise for the most part xNextTaskUnblockTime is set here - it is 0xffffffff if there are no blocked tasks: [https://github.com/FreeRTOS/FreeRTOS-Kernel/blob/V10.4.5/tasks.c#L381](https://github.com/FreeRTOS/FreeRTOS-Kernel/blob/V10.4.5/tasks.c#L4008) - what state are your tasks in?

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**Author:** ![sivasuren90](https://avatars.discourse-cdn.com/v4/letter/s/c5a1d2/32.png) [@sivasuren90](https://forums.freertos.org/u/sivasuren90)\
**Post date:** [November 14, 2021, 2:33am UTC](https://forums.freertos.org/t/sometimes-idle-task-receiving-finite-expected-idle-time-but-all-the-task-in-portmax-delay/13882/3 "2021-11-14T02:33:32Z")

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Thank you Richard Barry. I found Which task moving to ready state before free RTOS call idle task

Thanks again.