On 9/30/2010 5:55 PM, Varadarajan, Charulatha wrote:
Tony/ Benoit,
I think that disabling it should be done only if the CONFIG_OMAP_WDT
is not set.
How about disabling is done always unless CONFIG_WATCHDOG_NOWAYOUT
is set?
As given in the patch description, this patch does a disable of watchdog
timer, during init, to avoid the system rebooting that happens due to
enabling of watchdog timer after a reset of the module (during hwmod init).
According to the default WDT registers values, the system reboot would
happen in ~10s if watchdog is enabled with default values. Hence, after
a WDT module reset during init, the watchdog has to be disabled within 10s
otherwise the system will keep rebooting.
Hence irrespective of CONFIG_WATCHDOG_NOWAYOUT/ CONFIG_OMAP_WDT,
the watchdog timer needs to be disabled after a WDT reset has happened.
No, not necessarily, this is the whole point about a watchdog, you need
just need to ping it to prove that the system is alive.
In case you didn't notice, every watchdogs are started during a cold
reset since OMAP1610. Even Phoenix contains a watchdog that is started
by default.
This is by construction... and this is done like that for a good reason.
So stopping a watchdog just after the reset in a bootloader is not
necessarily the behavior that user of a watchdog are expecting,
otherwise it will not be started by default at boot time.
In your description, it looks like this behavior is a HW bug that we
have to fix... It is just the way it is supposed to work.
Regards,
Benoit
Later on, the watchdog timer probe would be called (if CONFIG_OMAP_WDT
is defined) which takes care of doing the regular the watchdog timer
settings. After this, normal operations like open, close, ioctl operations
are supported (if CONFIG_OMAP_WDT is defined).
Based on CONFIG_WATCHDOG_NOWAYOUT definition, disabling the watchdog
may/may not be supported.
Hence omap2_disable_wdt() introduced in this patch is not going to affect
the watchdog operations in anyway execpt that it is fixing the reboot issue
observed due to a watchdog timer reset. And this has to be done irrespective
of any OMAP watchdog timer related flags.
I guess, omap_wdt_disable() call during the WDT probe might be due to
similar reasons.
That way product kernels can set CONFIG_WATCHDOG_NOWAYOUT
and for the rest of us we can let fsck run the standard Linux way.
Tony
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