On 07/27/2014 04:18 PM, Rafael J. Wysocki wrote: > On Friday, July 25, 2014 02:06:48 PM Soren Brinkmann wrote: >> On platforms that do not power off during suspend, successfully entering >> suspend races with timers. >> >> The race happening in a couple of location is: >> >> 1. disable IRQs (e.g. arch_suspend_disable_irqs()) >> ... >> 2. syscore_suspend() >> -> timekeeping_suspend() >> -> clockevents_notify(SUSPEND) >> -> tick_suspend() (timers are turned off here) >> ... >> 3. wfi (wait for wake-IRQ here) >> >> Between steps 1 and 2 the timers can still generate interrupts that are >> not handled and stay pending until step 3. That pending IRQ causes an >> immediate - spurious - wake. >> >> The solution is to move the clockevents suspend/resume notification >> out of the syscore_suspend step and explictly call them at the appropriate >> time in the suspend/hibernation paths. I.e. timers are suspend _before_ >> IRQs get disabled. And accordingly in the resume path. >> >> Signed-off-by: Soren Brinkmann <soren.brinkm...@xilinx.com> >> --- >> Hi, >> >> This is my second shot at this. I followed John's suggestion to keep the >> timekeeping suspend where it is and just move the shutdown of the clockevent >> devices around. > John, what do you think?
I've not had the chance to take a closer look and do any testing. I suspect we'll need tgxl's input here as well. The change makes sense, but ordering modifications in this area tend to be fragile, as there are lots of implicit dependencies. thanks -john -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
