On Tue, Dec 09, 2014 at 12:38:09PM +0000, Krzysztof Kozlowski wrote: > On wto, 2014-12-09 at 13:29 +0100, Arnd Bergmann wrote: > > On Tuesday 09 December 2014 12:48:36 Krzysztof Kozlowski wrote: > > > Fix build failure of defconfig when PM_SLEEP is disabled (e.g. by > > > disabling SUSPEND) and CPU_IDLE enabled: > > > > > > arch/arm64/kernel/psci.c:543:2: error: unknown field ‘cpu_suspend’ > > > specified in initializer > > > .cpu_suspend = cpu_psci_cpu_suspend, > > > ^ > > > arch/arm64/kernel/psci.c:543:2: warning: initialization from incompatible > > > pointer type [enabled by default] > > > arch/arm64/kernel/psci.c:543:2: warning: (near initialization for > > > ‘cpu_psci_ops.cpu_prepare’) [enabled by default] > > > make[1]: *** [arch/arm64/kernel/psci.o] Error 1 > > > > > > The cpu_operations.cpu_suspend field exists only if ARM64_CPU_SUSPEND is > > > defined, not CPU_IDLE. > > > > > > Signed-off-by: Krzysztof Kozlowski <k.kozlow...@samsung.com> > > > > > > > No objection to fixing this obvious build bug, but why do we even have > > an ARM64_CPU_SUSPEND option? On ARM32 we only have the respective option > > because we have a random collection of platform specific drivers that > > use the symbols, but that's not the case on ARM64. > > I believe because of cpuidle. It's the same as on ARM32: the cpu_suspend > is used by both PM_SLEEP and CPU_IDLE.
I guess at some point we can replace (as a separate patch) ARM64_CPU_SUSPEND with PM_SLEEP. But what I don't fully understand, we can enable CPU_IDLE without ARM64_CPU_SUSPEND. However, the cpuidle-arm64.c driver will fail to link since it calls cpu_suspend(). Wouldn't it be better if ARM64_CPU_SUSPEND depends on CPU_PM (or replaced by it) rather than PM_SLEEP? Can we allow deeper idle states when CONFIG_SUSPEND is disabled? I see CONFIG_SUSPEND related to suspend-to-RAM (system standby) rather than CPU idle, in which case we may want to allow cpu_suspend when only CPU_IDLE is enabled (which implies CONFIG_CPU_PM). -- Catalin -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
