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. -- 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
