RTOS/SIMPLELINK-MSP432-SDK: Low Power Mode when no task active (move from TI-RTOS to SimpleLink/POSIX)

Got it sorted out now :

In the board file (in my case MSP_EXP432E401Y.c), the function that defines the power policy is registered in a static structure.

/*
 *  =============================== Power ===============================
 */
#include <ti/drivers/power/PowerMSP432E4.h>
const PowerMSP432E4_Config PowerMSP432E4_config = {
    .policyFxn = &PowerMSP432E4_sleepPolicy,
    .enablePolicy = true
};

I've placed a breakpoint in that function to see if it gets called and what it's doing.
It gets called and here's the logic:

#define DHCSR (*(volatile uint32_t *)0xE000EDF0)
#define C_DEBUGGEN 0x1

/*
 *  ======== PowerMSP432E4_sleepPolicy ========
 */
void PowerMSP432E4_sleepPolicy()
{
    /* invoke WFI only if CPU is not in debug mode */
    if (!(DHCSR & C_DEBUGGEN)) {
        __asm(" wfi");
    }
}

So if we're in debug mode, we don't sleep. When not in debug mode, the ARM WFI instruction is executed:

• An IRQ interrupt, regardless of the CPSR I-bit.
• An FIQ interrupt, regardless of the CPSR F-bit.
• An Imprecise Data abort, unless masked by the CPSR A-bit.
• A Debug Entry request, regardless of whether Debug is enabled.