On Saturday, March 07, 2015 12:29:33 PM Pavel Machek wrote: > On Sat 2015-03-07 12:06:45, Alexandre Belloni wrote: > > On 07/03/2015 at 11:39:39 +0100, Pavel Machek wrote : > > > > The Atmel watchdog can't be stopped once it's started. This is actually > > > > very useful so we can reset if suspend or resume failed, the only > > > > drawback is that you have to wake up from time to time (e.g. by using > > > > the RTC/RTT) to clear the watchdog and then go back to sleep ASAP. > > > > > > Yeah. So you do "echo mem > /sys/power/state", and few seconds/minutes > > > after watchdog kills the system. But you did not ask for dead system, > > > you asked for suspend. > > > > > > And while that behaviour is useful for you, I don't think it is > > > exactly useful behaviour, nor it is the behaviour user would expect. > > > > > > > I think you misunderstood, that is exactly the expected behaviour. This > > is hardware defined. Once the watchdog is started, nobody can stop it. > > Trying to change the mode register will result in a reset of the > > SoC. > > Well, it boils down to "what is stronger". Desire to suspend the > system, or desire to reboot the system. > > It is "echo mem > state", not "echo reboot > state". > > > It is documented in the datasheet and any user wanting another behaviour > > is out of luck. > > 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. -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- 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
