On 16/01/2015 12:10, Mason wrote:
I didn't find where WFI is called :-( In kernel/cpu/idle.c (file seems to have been removed in 3.15) cpu_idle_loop() calls arch_cpu_idle() http://lxr.free-electrons.com/source/kernel/cpu/idle.c?v=3.14#L98 In arch/kernel/process.c http://lxr.free-electrons.com/source/arch/arm/kernel/process.c?v=3.14#L173 /* * Called from the core idle loop. */ void arch_cpu_idle(void) { if (cpuidle_idle_call()) default_idle(); } default_idle calls cpu_do_idle (by default), a macro for cpu_v7_do_idle which executes dsb+wfi, BUT... ifndef CONFIG_CPU_IDLE then static inline int cpuidle_idle_call(void) { return -ENODEV; } Does that mean I MUST define CONFIG_CPU_IDLE if I want the idle loop to call wfi (to save power), even if I don't have a cpuidle driver?
For the record, I read the code wrong. cpuidle_idle_call() always returns -ENODEV, so the test "if (cpuidle_idle_call())" is always true, and we always call default_idle() and everything works as expected. Sorry for the noise. -- To unsubscribe from this list: send the line "unsubscribe cpufreq" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
