On Wed, Apr 03, 2013 at 08:50:26AM -0700, Guenter Roeck wrote: > On Wed, Apr 03, 2013 at 08:06:59AM -0700, Tony Chung wrote: > > On Tue, Apr 2, 2013 at 9:21 PM, Guenter Roeck <linux@xxxxxxxxxxxx> wrote: > > > > > > > > > > > What is the exact chip type in your system ? I want to have a look into the > > > datasheet; maybe I can find out how it can trigger without causing a reset. > > > > Winbond 83627HF chip > > Followup: what chip revision ? Revision G or later have a new configuration bit, bit 3 of CR E7 on logical device A. SELWDTORST. Watch Dog Timer Reset Control. = 0 is reset by LPC_RST. = 1 is reset by PWR_OK. I could imagine that the WDT logic is never correctly initialized in your system, which might explain the behavior. If so, your code is indeed correct (or the best I could come up with too), as we would have to ensure that the wdt subsystem is initialized correctly by writing into all its registers. Given that, I would suggest to re-submit the patch with a different explanation (we don't know if the wdt really started running, all we know is that the expired bit is set), and I'll give it an Acked-by. Something along the line of "Observed that the Watchdog Timer Status bit can be set when the driver is loaded. Reset it during initialization. The time-out value must be set to 0 explicitly in this case to prevent an immediate reset". Thanks, Guenter > > I believe BIOS has watchdog disabled otherwise it would have reboot the box. > > However, the timer just start counting. > > > > Comparing to ipmi_watchdog, you can do this: > > modprobe ipmi_watchdog ... start_now=0 ...action=<> nowayout=1 > > > > So it is possible to load the driver without start counting. > > > That is a different driver, though. you don't have the start_now option here. > > > Notice it is an else, so t is actually 0 already (i.e. expired or > > never start running): > > Still no idea why that would cause the system to reboot when you reset > the trigger without setting t to 0 again (or why the system doesn't reset > in the first place if the watchdog already triggered). > > I am not really sure what the best approach is here, so let's leave it > up to the maintainer to decide which way to go. > > Thanks, > Guenter > -- > 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 > -- 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
