Hello,
I'm using linux-2.6.35.3 on a pandaboard taking power measurements in different
idle states (I've written a userspace governor for cpuidle).
It seems like the code which is supposed to put the cores in deep sleep never
actually gets called, see code below with my comments...
Taken from arch/arm/mach-omap2/cpuidle44xx.c, omap4_enter_idle, which gets
called by cpuidle:
===============
/*
* Do only WFI for non-boot CPU(aux cores)
*/
if (dev->cpu) {
wmb();
do_wfi();
goto return_sleep_time;
}
So on OMAP 4430, CPU1 never goes deeper than WFI?
/*
* Do only a WFI as long as CPU1 is online
*/
if (num_online_cpus() > 1) {
wmb();
do_wfi();
goto return_sleep_time;
}
So while CPU1 is online (it never goes offline due to the above code) CPU0 will
never go deeper than WFI?
/*
* Hold on till CPU1 hits OFF
*/
cpu1_state = pwrdm_read_pwrst(cpu1_pd);
if (cpu1_state != PWRDM_POWER_OFF) {
wmb();
do_wfi();
goto return_sleep_time;
}
It seems like CPU1 will never 'hit off' ?
if (cx->type > OMAP4_STATE_C1)
clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu_id);
#ifdef CONFIG_PM_DEBUG
pwrdm_pre_transition();
#endif
The code below never gets called, therefore neither CPU0, CPU1 nor the MPU go
into a deeper sleep state?
pwrdm_set_logic_retst(mpu_pd, cx->mpu_logic_state);
omap4_set_pwrdm_state(mpu_pd, cx->mpu_state);
omap4_set_pwrdm_state(core_pd, cx->core_state);
omap4_enter_sleep(dev->cpu, cx->cpu0_state);
=================
Can someone clarify for me?
Cheers,
Etienne Le Sueur
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