On 10/03/2015 at 23:31:52 +0100, Rafael J. Wysocki wrote : > On Tuesday, March 10, 2015 10:33:17 PM Alexandre Belloni wrote: > > Hi, > > > > On 09/03/2015 at 15:30:01 +0100, Rafael J. Wysocki wrote : > > > > > > Actaully, your platform should just refuse to enter suspend-to-RAM > > > > > > when hw watchdog is enabled. > > > > > > > > > > Quite likely, depending on how exactly the suspend is implemented. > > > > > > > > > > > > > We've had absolutely zero complain on that. It is quite clear in the > > > > datasheet that failing to refresh the watchdog once started will lead to > > > > a reset and that it is impossible to stop. > > > > It is actually quite convenient to also ensure that you can actually > > > > wake up from suspend because that can obviously go wrong. > > > > > > I gather then that the suspend implementation is such that touching the > > > watchdog periodically while suspended is not a problem. > > > > > > Again, can you please tell me how suspend is implemented on at91? > > > > > > > It actually depends on the architecture (at91rm9200, at91sam9 or sama5) > > but basically, the clocks are switched off in almost all the peripheral > > drivers then the ram self refresh activated, the master clock is > > switched off using code running from SRAM and the core is then waiting > > for interrupt. > > OK, so it looks like enable_irq_wake() doesn't actually affect the hardware > on those platforms, is that correct? > I didn't exactly look in details but apart from the wakeup from gpio handling (keeping the pio controller clocked in the case one of its gpio has wakeup enabled), I don't think it does much more. It uses irq_gc_set_wake(). -- Alexandre Belloni, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
