On Tuesday 20 of August 2013 09:48:25 Stephen Boyd wrote: > 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. Right, I could have added a sentence or two about this. > 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). Yes, cpu_present_mask might be better indeed. Best regards, Tomasz -- 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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