On Thu, 2013-06-13 at 17:30 +0800, Daniel Lezcano wrote: > On 06/13/2013 04:13 AM, Joseph Lo wrote: > > On Thu, 2013-06-13 at 01:41 +0800, Stephen Warren wrote: > >> On 06/04/2013 03:40 PM, Daniel Lezcano wrote: > >>> On 06/04/2013 12:48 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 <josephl@xxxxxxxxxx> > >>> > >>> I would like to understand why there is a WARN with the > >>> CPUIDLE_FLAG_TIMER_STOP flag set before queuing this patch and ensure it > >>> is not the tree hiding the forest. > >> > >> Joseph, are you planning to post an updated series or respond to resolve > >> Daniel's question? > > > > I need more time to investigate the detail about what caused the WARN > > when apply the flag. And what's the difference if we didn't enable > > CONFIG_CPU_IDLE_MULTIPLE_DRIVERS, then it only applies > > CLOCK_EVT_NOTIFY_BROADCAST_ON on CPU0. > > I think I got it for this one. It is a bug in the cpuidle driver's code. > > cpuidle_register_driver does get_cpu => CPU0 > > Then __cpuidle_register_driver(drv, <CPU0>) > > => __cpuidle_driver_init(drv, <CPU0>) > > Hence, the timer broadcast is initialized only for cpu0. > > That should have been fixed with: > OK, thanks. > commit 82467a5a885ddd9f80309682159da8db510e7832 > Author: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx> > Date: Fri Jun 7 21:53:09 2013 +0000 > > cpuidle: simplify multiple driver support > > Commit bf4d1b5 (cpuidle: support multiple drivers) introduced support > for using multiple cpuidle drivers at the same time. It added a > couple of new APIs to register the driver per CPU, but that led to > some unnecessary code complexity related to the kernel config options > deciding whether or not the multiple driver support is enabled. The > code has to work as it did before when the multiple driver support is > not enabled and the multiple driver support has to be compatible with > the previously existing API. > > Remove the new API, not used by any driver in the tree yet (but > needed for the HMP cpuidle drivers that will be submitted soon), and > add a new cpumask pointer to the cpuidle driver structure that will > point to the mask of CPUs handled by the given driver. That will > allow the cpuidle_[un]register_driver() API to be used for the > multiple driver support along with the cpuidle_[un]register() > functions added recently. > > [rjw: Changelog] > Signed-off-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > > > > Why if I am moving the > > clockevent_notify of CLOCK_EVT_NOTIFY_BROADCAST_EXIT before > > "local_irq_enable" in the > > "cpuidle_enter_state" (drivers/cpuidle/cpuidle.c), then the warning > > message gone? > > Is the warning coming immediately, at the first time > CLOCK_EVT_NOTIFY_BROADCAST_EXIT is invoked or can it occur at different > moment ? > Not exactly at the 1st time, it may happen in the 3rd to 10th time. But it only happens once. I mean I did check the tick_broadcast_pending_mask, it only happens once the CPU didn't clear the tick_broadcast_pending_mask after CLOCK_EVT_NOTIFY_BROADCAST_EXIT. And cause the warning message. Then I didn't see it happen anymore. -- 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
