Re: [PATCH v2] watchdog: omap_wdt: Add 'early_disable' module parameter

[Rostislav Lisovy]

On Ät, 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.


> 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.

Best regards;
Rostislav


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