Messages in this thread | | | Date | Mon, 15 Dec 2014 18:32:44 +0000 | From | Lorenzo Pieralisi <> | Subject | Re: [PATCH] arm64: psci: Fix build breakage without PM_SLEEP |
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On Mon, Dec 15, 2014 at 05:46:22PM +0000, Catalin Marinas wrote: > On Fri, Dec 12, 2014 at 03:06:08PM +0000, Lorenzo Pieralisi wrote: > > On Tue, Dec 09, 2014 at 04:15:11PM +0000, Catalin Marinas wrote: > > > 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.kozlowski@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? > > > > I think that ARM64_CPU_SUSPEND should depend on PM_SLEEP || CPU_IDLE, > > That's what we do with CPU_PM, we select it if SUSPEND || CPU_IDLE > (PM_SLEEP is default yes if SUSPEND). > > > if CPU_IDLE is enabled it is certainly because some idle states are > > expected to be present, true, not all of them lose context (which is > > why ARM64_CPU_SUSPEND is needed, to save/restore context and clean > > it to RAM), but I think that's too fine grain, making it depend on > > CPU_IDLE should be ok. > > > > Having CPU_IDLE enabled without arm64 cpuidle driver enabled (which > > selects ARM64_CPU_SUSPEND) is useless at the moment. > > Ah, so we can force a selection even if it doesn't meet its > dependencies like PM_SLEEP (which depends on SUSPEND). > > Can we just get rid of ARM64_CPU_SUSPEND altogether and use CPU_PM > instead?
Yes, it looks like the best option to me, I will put together a patch shortly.
Thanks, Lorenzo
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