2008-05-27 06:46:08     Watchdog in 2008R1

2008-05-27 06:46:08     Watchdog in 2008R1

Sergey Panov (RUSSIAN FEDERATION)

Message: 56299   

I have the last version of uClinux.

The option `Device Nodes' is Dynamic.

The option `Blackfin On-Chip Watchdog Timer' is checked.

I see the node /dev/watchdog.

But the function open("/dev/watchdog", O_WRONLY) returns the result -1.

Help, please!

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2008-05-28 03:07:22     Re: Watchdog in 2008R1

Mike Frysinger (UNITED STATES)

Message: 56316   

did you create the device node yourself ?

the return value of -1 really doesnt tell you much ... you have to look at errno to better figure out what the problem is

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2008-05-28 06:00:17     Re: Watchdog in 2008R1

Sergey Panov (RUSSIAN FEDERATION)

Message: 56341   

No, I didn't create it myself.

errno = 16 - `Device or resource busy'.

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2008-05-28 11:17:35     Re: Watchdog in 2008R1

Mike Frysinger (UNITED STATES)

Message: 56354   

then there you go ... you probably already have something already opening the watchdog, and since only one application can open the watchdog at a time ...

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2008-05-29 03:57:45     Re: Watchdog in 2008R1

Sergey Panov (RUSSIAN FEDERATION)

Message: 56391   

Mike, thank you. You are quite right, the process opening the watchdog is `/bin/watchdogd -f -s'. I don't understand the mechanism of launching this process. So, after the line

int main(int argc, char *argv[]) {

of the file .../user/blkfin-apps/watchdogd/watchdogd.c I inserted `return 0;'. After that I became to receive the message

init: /bin/watchdogd respawning too fast

Then I inserted

while (1)

  sleep(1);

Now `init' is happy and my watchdog works right. But I'm not very happy because I don't know how to do all of this properly.

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2008-05-29 11:35:49     Re: Watchdog in 2008R1

Mike Frysinger (UNITED STATES)

Message: 56411   

you enabled the default watchdog daemon in the dist ... that will maintain /dev/watchdog for you.  if you want to maintain it yourself, then you need to disable the watchdog daemon in the user configuration menu.

you're correct in that modifying random programs is probably never the right way to do things.

see Blackfin app programs -> watchdog

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2008-05-29 14:45:16     Re: Watchdog in 2008R1

Sergey Panov (RUSSIAN FEDERATION)

Message: 56426   

Thank you.