On Fri, May 02, 2014 at 09:29:25PM -0700, Guenter Roeck wrote: > > > + if (wdd->ops->reboot) > > > + wdd_reboot_dev = wdd; > > > + > > > > Overall, it looks really great, but I guess we can make it a > > list. Otherwise, we might end up in a situation where we could not > > reboot anymore, like this one for example: > > - a first watchdog is probed, registers a reboot function > > - a second watchdog is probed, registers a reboot function that > > overwrites the first one. > > - then, the second watchdog disappears for some reason, and the > > reboot is set to NULL > > > I thought about that, but how likely (or unlikely) is that to ever happen ? > So I figured it is not worth the effort, and would just add complexity without > real gain. We could always add the list later if we ever encounter a situation > where two watchdogs in the same system provide a reboot callback. The A31 we were discussing about in the other thread that doesn't have a watchdog driver yet has four, identical, watchogs. I'm not really concerned about the mentionned issue, since they will never be removed, but the situation might happen with an on-SoC watchdog and an i2c one (if that even exists). But yes, right, that can be postponed. > > Or maybe we can just use the start callback, with the min timeout already > > registered, and prevent the user to kick the watchdog. > > > Doesn't always work, unfortunately, even now. The moxart driver causes > an explicit and immediate reset. Also, some watchdogs don't reset the system > directly but get an interrupt, which then calls the reset handler. Which, > in our case, would call the start callback again, and you would have an endless > loop. Ok. You have my Acked-by then. Thanks! Maxime -- Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com
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