On 07/19/2013 09:14 AM, Joseph Lo wrote: > On Thu, 2013-07-18 at 20:41 +0800, Daniel Lezcano wrote: >> On 07/18/2013 01:08 PM, Joseph Lo wrote: >>> On Thu, 2013-07-18 at 04:31 +0800, Stephen Warren wrote: >>>> On 07/17/2013 04:15 AM, Joseph Lo wrote: >>>>> On Wed, 2013-07-17 at 03:51 +0800, Stephen Warren wrote: >>>>>> On 07/16/2013 05:17 AM, Joseph Lo wrote: >>>>>>> On Tue, 2013-07-16 at 02:04 +0800, Stephen Warren wrote: >>>>>>>> On 06/25/2013 03:23 AM, Joseph Lo wrote: >>>>>>>>> Use the CPUIDLE_FLAG_TIMER_STOP and let the cpuidle framework >>>>>>>>> to handle the CLOCK_EVT_NOTIFY_BROADCAST_ENTER/EXIT when entering >>>>>>>>> this state. >>>> ... [ discussion of issues with Joesph's patches applied] >>>>> >>>>> OK. I did more stress tests last night and today. I found it cause by >>>>> the patch "ARM: tegra: cpuidle: use CPUIDLE_FLAG_TIMER_STOP flag" and >>>>> only impact the Tegra20 platform. The hot plug regression seems due to >>>>> this patch. After dropping this patch on top of v3.11-rc1, the Tegra20 >>>>> can back to normal. >>>>> >>>>> And the hop plug and suspend stress test can pass on Tegra30/114 too. >>>>> >>>>> Can the other two patch series for Tegra114 to support CPU idle power >>>>> down mode and system suspend still moving forward, not be blocked by >>>>> this patch? >>>>> >>>>> Looks the CPUIDLE_FLAG_TIMER_STOP flag still cause some other issue for >>>>> hot plug on Tegra20, I will continue to check this. You can just drop >>>>> this patch. >>>> >>>> OK, if I drop that patch, then everything on Tegra20 and Tegra30 seems >>>> fine again. >>>> >>>> However, I've found some new and exciting issue on Tegra114! >>>> >>>> With unmodified v3.11-rc1, I can do the following without issue: >>>> >>>> * Unplug/replug CPUs, so that I had all combinations of CPU 1, 2, 3 >>>> plugged/unpplugged (with CPU 0 always plugged). >>>> >>>> * Unplug/replug CPUs, so that I had all combinations of CPU 0, 1, 2, 3 >>>> plugged/unpplugged (with the obvious exception of never having all CPUs >>>> unplugged). >>>> >>>> However, if I try this with your Tegra114 cpuidle and suspend patches >>>> applied, I see the following issues: >>>> >>>> 1) If I boot, unplug CPU 0, then replug CPU 0, the system immediately >>>> hard-hangs. >>>> >>> Sorry, I didn't apply the hotplug stress test on CPU0 too much. Because >>> all of our use cases and stress tests are focused on secondary CPUs >>> only. >>> >>> After doing some tests, here is my summary. This issue happens after we >>> support CPU idle power-down mode and relates to PMC or flow controller I >>> believe. >>> >>> i) on top of v3.11-rc1 (only support WFI in CPU idle) >>> When hot unplug CPU0, the PMC can power gate and put it into reset >>> state. This is what I expect and also true on all the other secondary >>> CPUs. The flow controller can maintain the CPU power state machine as >>> what we want. >>> >>> ii) on top of v3.11-rc1 + CPU idle power down mode support >>> a) I saw most of the time the CPU0,1,2,3 were in power down and reset >>> status. That means the idle power down mode works fine. >>> >>> b) Testing with the CPU hotplug stress test with the secondary CPUs (not >>> include CPU0), the result is good too. >>> >>> c) Testing hot plug on CPU0 with CPUIDLE_FLAG_TIMER_STOP apply or not >>> apply (Note 1), the result shows not good to me. The CPU0 have already >>> gone into WFI and the flow controller is set as WAITFOREVENT mode. But >>> the PMC always can't power gate CPU0 and sometimes can put it into >>> reset, but sometimes can't. That's why you can see it hanging after >>> unplug CPU0 sometimes. >> >> Are sure coupled idle state support hotplug and especially the cpu0 >> hotplug ? > > Tegra114 didn't use coupled idle framework. Ok, so the problem occurs with the CPUIDLE_FLAG_TIMER_STOP flag only on tegra114, right ? Sorry, I am a bit lost :) -- <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | <http://twitter.com/#!/linaroorg> Twitter | <http://www.linaro.org/linaro-blog/> Blog -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html