Hi, 在 2014年08月29日 19:22, Mark Rutland 写道: >> 在 2014年08月28日 23:11, Mark Rutland 写道: >>> To clarify: if there are low power states that the CPU can enter where >>> we lose state, then this patch isn't correct. >> Right now, the software of RK3288 SoC only support CPU hotplug >> (cpu_on/off) and power off all CPUs on suspend. > Sure, but that's a Linux implementation detail rather than a fixed > property of the hardware. Given those states exist, the "always-on" > property is not appropriate. > >> We do not implement cpuidle to power off CPU. Do you think we should >> introduce a broadcast timer? > If one is present, yes. > >> On our early kernel, I never see any interrupt on a broadcast timer >> (yes, we implement it with a external timer). > That's fine; Linux doesn't need to use it just yet. However, when we > want to use low power states later, it will be necessary to enable > placing all CPUS into a low power state. > > If your external timer is already supported by an existing driver, there > is no reason not to add it now. > >>> A more general approach would be to enable the broadcast hrtimer for >>> arm, as has been done for arm64. >> Yes. I think it should be done by arm framework. > Patches welcome. > > I also think it would make sense to enable this for arm. > > Thanks, > Mark. > > Okay, so this patch is wrong as I expected. Thank you! -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
