Hello Harald, On Sun, Nov 29, 2015 at 11:41:22AM +0100, Harald Geyer wrote: > On 27.11.2015 11:44, Uwe Kleine-König wrote: > >Hello Harald, > > > >On Fri, Nov 27, 2015 at 11:02:54AM +0100, Uwe Kleine-König wrote: > >>On Thu, Nov 26, 2015 at 02:39:45PM +0100, Harald Geyer wrote: > >>> Uwe Kleine-König writes: > >>> > On Wed, Oct 07, 2015 at 12:19:12PM +0000, Harald Geyer wrote: > >>> > > This device doesn't provide any information about boot status. > >>> > > As workaround we use a persitent bit to track watchdog activity. > >>> > > >>> > Hmm, so you set a bit in a persistent register iff the watchdog is > >>> > running. And if that bit is set during probe you assume the > >>watchdog > >>> > reset the machine. But this also happens, when the user presses the > >>> > reset button which makes the detection unreliable. > >>> > >>> Yes, kind of. I'm using this driver on an imx233-olinuxino, where the > >>> reset button causes the device to power cycle and thus clears the > >>> persitent bit. So I can't test your case, but surely there are some > >>paths > >>> into reset, that don't clear the bit and cause false positives. > >> > >>OK, I found a i.MX28 machine in our repository: > >> > >> barebox# mw 0x80056080 0xbabecafe > >> barebox# boot > >> ... > >> linux# reboot > >> barebox# md 0x80056080+4 > >> 80056080: babecafe > >> > >>After a power cycle the value disappears (I didn't check the details, if > >>there is a battery it might be empty). > > Are there any concerns left on your side? Ie do you want me to do > any additional tests before sending v4 of this patch with the > whitespace changes and added URL to the freescale kernel? I just notice that I failed to do the proper test. I.e. I reset the machine using "reboot" instead of a reset button. But I'd expect that doing the latter also keeps the value of the persistant register, which would make your patch wrong here. I will check that tomorrow when I can make someone do this test for me. (I'm 600 km from the machine above away.) Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ | -- To unsubscribe from this list: send the line "unsubscribe linux-watchdog" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
