From: Guenter Roeck <linux@roeck-us.net> To: Rostislav Lisovy <lisovy@gmail.com> Cc: Wim Van Sebroeck <wim@iguana.be>, linux-watchdog@vger.kernel.org, linux-kernel@vger.kernel.org, sojkam1@fel.cvut.cz, michal.vokac@comap.cz, Rostislav Lisovy <lisovy@merica.cz> Subject: Re: [PATCH v2] watchdog: omap_wdt: Add 'early_disable' module parameter Date: Tue, 23 Sep 2014 09:14:40 -0700 [thread overview] Message-ID: <20140923161440.GC20591@roeck-us.net> (raw) In-Reply-To: <1411469087.32524.6.camel@lp-lvrv.comap.cz> On Tue, Sep 23, 2014 at 12:44:47PM +0200, Rostislav Lisovy wrote: > On Čt, 2014-09-18 at 21:12 -0700, Guenter Roeck wrote: > > How about reading the OMAP_WATCHDOG_SPR register ? > > Unfortunately this would be not only extremely fragile (someone writes > correct start sequence followed by some garbage -- WD is running and we > are reading garbage) but according to some experiments seems not to work > at all (I am reading "0" even for a running WD probably as a result to > the pm_runtime_get_sync() call). > > One of the TI employees on the TI forum confirmed (I know this is not a > rock-solid information) that it is not possible to safely determine if > the WD is running or not. > Annoying, but I guess we'll have to live with that. > > > Either case, you can not issue a message about the watchdog being > > stopped or started if you don't know if it was actually stopped > > or started. Also, if you don't really know if the watchdog was > > stopped or started, all you can do is to either stop or start it, > > without judgment about its previous condition. > > You are right. I was blinded by our use case where the watchdog is > always started by the bootloader. > I will wait to see if the WATCHDOG_KEEP_ON will be integrated and then I > will add the feature for the omap_wdt. > I would predict that it will be accepted. For my part I am not happy with the name, though, and I'll have to find the time to thoroughly review and, if possible, test it. Guenter
WARNING: multiple messages have this Message-ID (diff)
From: Guenter Roeck <linux@roeck-us.net> To: Rostislav Lisovy <lisovy@gmail.com> Cc: Wim Van Sebroeck <wim@iguana.be>, linux-watchdog@vger.kernel.org, linux-kernel@vger.kernel.org, sojkam1@fel.cvut.cz, michal.vokac@comap.cz, Rostislav Lisovy <lisovy@merica.cz> Subject: Re: [PATCH v2] watchdog: omap_wdt: Add 'early_disable' module parameter Date: Tue, 23 Sep 2014 09:14:40 -0700 [thread overview] Message-ID: <20140923161440.GC20591@roeck-us.net> (raw) In-Reply-To: <1411469087.32524.6.camel@lp-lvrv.comap.cz> On Tue, Sep 23, 2014 at 12:44:47PM +0200, Rostislav Lisovy wrote: > On Čt, 2014-09-18 at 21:12 -0700, Guenter Roeck wrote: > > How about reading the OMAP_WATCHDOG_SPR register ? > > Unfortunately this would be not only extremely fragile (someone writes > correct start sequence followed by some garbage -- WD is running and we > are reading garbage) but according to some experiments seems not to work > at all (I am reading "0" even for a running WD probably as a result to > the pm_runtime_get_sync() call). > > One of the TI employees on the TI forum confirmed (I know this is not a > rock-solid information) that it is not possible to safely determine if > the WD is running or not. > Annoying, but I guess we'll have to live with that. > > > Either case, you can not issue a message about the watchdog being > > stopped or started if you don't know if it was actually stopped > > or started. Also, if you don't really know if the watchdog was > > stopped or started, all you can do is to either stop or start it, > > without judgment about its previous condition. > > You are right. I was blinded by our use case where the watchdog is > always started by the bootloader. > I will wait to see if the WATCHDOG_KEEP_ON will be integrated and then I > will add the feature for the omap_wdt. > I would predict that it will be accepted. For my part I am not happy with the name, though, and I'll have to find the time to thoroughly review and, if possible, test it. Guenter -- To unsubscribe from this list: send the line "unsubscribe linux-watchdog" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
next prev parent reply other threads:[~2014-09-23 16:14 UTC|newest] Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top 2014-09-16 14:20 [PATCH v2] watchdog: omap_wdt: Add 'early_disable' module parameter Rostislav Lisovy 2014-09-16 15:49 ` Guenter Roeck 2014-09-17 15:22 ` Rostislav Lisovy 2014-09-19 4:12 ` Guenter Roeck 2014-09-23 10:44 ` Rostislav Lisovy 2014-09-23 16:14 ` Guenter Roeck [this message] 2014-09-23 16:14 ` Guenter Roeck
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