On 08/20/13 09:41, Tomasz Figa wrote: > On Tuesday 20 of August 2013 09:33:31 Stephen Boyd wrote: >> On 08/20/13 09:11, Tomasz Figa wrote: >>> Sometimes it is necessary to fix interrupt affinity to an offline CPU, >>> for example in initialization of local timers. This patch modifies >>> .set_affinity() operation of irq-gic driver to fall back to any >>> possible >>> CPU if no online CPU can be found in requested CPU mask. >>> >>> This fixes broken Exynos4210 support since commit >>> >>> ee98d27df6 ARM: EXYNOS4: Divorce mct from local timer API >>> >>> caused by timer initialization code unable to set affinity for local >>> timer interrupts. >> Care to elaborate further? I don't see how the interrupt affinity is set >> for a CPU that isn't online because the mct code runs on the CPU that >> the affinity is being set to. > Well, please look at secondary_start_kernel() in arch/arm/kernel/smp.c [1]. > You can see that notify_cpu_starting() (line 348) that fires the notifier > registered in MCT driver is called before set_cpu_online() (line 359) that > marks the CPU as online. Also notice that, originally, local timer > initialization was happening after set_cpu_online() - see line 365. > > Great, thank you. Please put this information in the commit text next time. I wonder if we shouldn't make the cpumask_any_and() work on the present mask instead? If we ever support physical hotplug on ARM I think we wouldn't want to allow interrupts to go to CPUs that aren't even present (but still possible). -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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