# Watchdog for other subsystems

Source: [https://docs.qualcomm.com/doc/80-88500-4/topic/70_Watchdog_for_other_subsystems.html](https://docs.qualcomm.com/doc/80-88500-4/topic/70_Watchdog_for_other_subsystems.html)

There are software and hardware watchdogs on modem peripheral subsystem (MPSS),
    application DSP (ADSP), and compute DSP (CDSP).

## Software watchdog

There is a software watchdog (WD) on MPSS, ADSP, and CDSP. Each user task registers to the dog
        task. All tasks must ping to dog task within 10 s. If it does not do so, the dog task
        detects it and falls into software error fatal.

## Hardware watchdog

- On MPSS, ADSP, and CDSP, the dog task pets the subsystem (SS) WD hardware every 100 ms. If the
          dog task does not pet it for 500 ms, the SS WD bark fast interrupt request (FIQ) is fired
          and it falls into software error fatal.
- On ADSP and CDSP, the hardware WD bark (FIQ) is fired every 500 ms seconds and the FIQ handler
          pets the hardware WD. This is not an error fatal condition.
- If the hardware WD bark is not properly handled (that is, if the software does not fall into an
          error fatal) then a nonmaskable interrupt (NMI) is fired in 700 ms. The Qualcomm Real Time
          OS for Hexagon processor (QuRT) traps it and flushes the cache, saves TCM, saves register
          values, and then waits for the hardware WD bite.
- If the hardware WD is not petted within 800 ms, the hardware WD bite is fired and the subsystem
          is reset. It then notifies “WD fired” to HLOS in the application processor. In this case,
          the cache, register values, and contents of TCM may not be saved.

**Parent Topic:** [Watchdog](https://docs.qualcomm.com/doc/80-88500-4/topic/68_Watchdog.html)

Last Published: Aug 18, 2023

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