From mboxrd@z Thu Jan 1 00:00:00 1970 From: daniel.lezcano@linaro.org (Daniel Lezcano) Date: Fri, 31 May 2013 15:18:35 +0200 Subject: [PATCH 3/3] ARM: tegra114: cpuidle: add powered-down state In-Reply-To: <1370000680.7804.83.camel@jlo-ubuntu-64.nvidia.com> References: <1369912782-30663-1-git-send-email-josephl@nvidia.com> <1369912782-30663-4-git-send-email-josephl@nvidia.com> <51A763BD.6070001@linaro.org> <1369991550.7804.37.camel@jlo-ubuntu-64.nvidia.com> <51A86D11.8060305@linaro.org> <1369997278.7804.73.camel@jlo-ubuntu-64.nvidia.com> <1369999870.7804.78.camel@jlo-ubuntu-64.nvidia.com> <1370000680.7804.83.camel@jlo-ubuntu-64.nvidia.com> Message-ID: <51A8A32B.6080303@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 05/31/2013 01:44 PM, Joseph Lo wrote: > On Fri, 2013-05-31 at 19:31 +0800, Joseph Lo wrote: >> On Fri, 2013-05-31 at 18:47 +0800, Joseph Lo wrote: >>> On Fri, 2013-05-31 at 17:27 +0800, Daniel Lezcano wrote: >>>> On 05/31/2013 11:12 AM, Joseph Lo wrote: >>>>> Hi Daniel, >>>>> >>>>> Thanks for your review. >>>>> >>>>> On Thu, 2013-05-30 at 22:35 +0800, Daniel Lezcano wrote: >>>>>> On 05/30/2013 01:19 PM, Joseph Lo wrote: >>>>>>> This supports CPU core power down on each CPU when CPU idle. When CPU go >>>>>>> into this state, it saves it's context and needs a proper configuration >>>>>>> in flow controller to power gate the CPU when CPU runs into WFI >>>>>>> instruction. And the CPU also needs to set the IRQ as CPU power down idle >>>>>>> wake up event in flow controller. >>>>>>> >>>>>>> Signed-off-by: Joseph Lo >>>>>>> --- >>>>>> >>>>>> Hi Joseph, >>>>>> >>>>>> a new flag has been added in the cpuidle framework to let this one to >>>>>> handle the timer broadcast : CPUIDLE_FLAG_TIMER_STOP >>>>>> >>>>>> It is the commit b60e6a0eb0273132cbb60a9806abf5f47a4aee1c >>>>>> >>>>>> You can get rid of the clockevent notify stuff by adding this flag to >>>>>> the state. >>>>>> >>>>> >>>>> I just tested this flag on Tegra20, 30 and 114. It is only OK on >>>>> Tegra20. It caused a warning message below on Tegra30/114 at boot time. >>>>> >>>>> I gave it a quick check I found it can't clean >>>>> tick_broadcast_pending_mask sometimes if apply the flag. But I keep the >>>>> code right now it's always OK. Not sure why? >>>> >>>> Is it possible you didn't intialized the timer broadcast with >>>> CLOCK_EVT_NOTIFY_BROADCAST_ON in the driver and then this one is >>>> actually disabled for you driver ? >>>> >>> I found if I don't apply the CPUIDLE_FLAG_TIMER_STOP flag, the function >>> "cpuidle_setup_broadcast_timer" (drivers/cpuidle/driver.c) would not be >>> called. Then it's OK. >>> >>> If I apply this flag (with no CONFIG_CPU_IDLE_MULTIPLE_DRIVERS), the >>> cpuidle_register_driver only register for CPU0. Then the >>> "cpuidle_setup_broadcast_timer" only turn on for CPU0. I think this >>> might be the root cause. Not sure this also can reproduce on the other >>> SoCs? >>> >> Looks it's not related to CLOCK_EVT_NOTIFY_BROADCAST_ON. I still saw the >> warning message even enable CONFIG_CPU_IDLE_MULTIPLE_DRIVERS. But if I >> move the clockevent_notify of CLOCK_EVT_NOTIFY_BROADCAST_EXIT from idle >> framework back to driver, then everything is OK. >> > Once I move the clockevent_notify of CLOCK_EVT_NOTIFY_BROADCAST_EXIT > right after "local_irq_enable" in the > "cpuidle_enter_state" (drivers/cpuidle/cpuidle.c). Then the warning > message shows up. Is it possible you pastebin you kernel config file ? I would like to check a couple of things before investigating the code. Thanks -- Linaro.org ? Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog