Update: disabling the OMAP watchdog and enabling the TWL4030 watchdog does work; the TWL wdt is able to reboot the COM all the way.

So the question is: what is missing in the OMAP wdt?


On Fri, Apr 20, 2012 at 6:51 PM, Vikram Godbole <vikram.godbole@gmail.com> wrote:

Hi all,

I have a couple of questions on the watchdog timer. I am working on Rowboat kernel 2.6.37, running on a WaterStorm COM/Chestnut43.

1. The default config has the following options enabled (and I see this in current Sakoman configs as well):

CONFIG_OMAP_WATCHDOG=y
CONFIG_TWL4030_WATCHDOG=y

Both, the omap and twl4030 watchdog drivers register with minor number WATCHDOG_MINOR. The OMAP driver loads first, and since a device with that minor is already registered, the loading of the TWL4030 watchdog always fails:

twl4030_wdt twl4030_wdt: Failed to register misc device : retval -16
twl4030_wdt: probe of twl4030_wdt failed with error -16

What is the intent here? Surely both watchdog drivers cannot coexist unless the minor numbers are changed? Should only one of the two be enabled by default?


2. I tried running the demo here with the omap watchdog (which is the one that gets loaded first):

http://embeddedfreak.wordpress.com/2010/08/23/howto-use-linux-watchdog/

and sure enough, if the watchdog isn't kicked, the COM reboots... or rather, tries to. The LCD goes gray and gets bands on it which makes it seem like the machine is trying to reboot- but the reboot doesn't complete. I have to manually press the RESET button on the Chestnut board to reboot. Why is this? Isn't the OMAP watchdog driver capable of rebooting the COM? Or is some other functionality needed for that?
I had read on this list sometime back that there is an issue with the OMAP watchdog driver w.r.t. the DM37x CPUs on the Storm series COMs- is that true? I have not tried disabling the OMAP watchdog and enabling the one on the TWL yet.

Thanks,
Vikram