Re: [PATCH 1/2] Add a simple watchdog framework

[Sascha Hauer <s.hauer@pengutronix.de>]

On Mon, Jun 25, 2012 at 02:45:43PM +0200, Juergen Beisert wrote:
> Sascha Hauer wrote:
> > On Fri, Jun 22, 2012 at 11:54:02AM +0200, Juergen Beisert wrote:
> > > This patch adds a simple wd command which can setup, trigger and stop a
> > > watchdog on the platform.
> > >
> > > +static int do_wd(int argc, char *argv[])
> > > +{
> > > +	int rc;
> > > +
> > > +	if (argc > 1) {
> > > +		if (isdigit(*argv[1])) {
> > > +			timeout = simple_strtoul(argv[1], NULL, 0);
> > > +		} else {
> > > +			printf("numerical parameter expected\n");
> > > +			return 1;
> > > +		}
> > > +	}
> > > +
> > > +	rc = watchdog_set_timeout(timeout);
> > > +	if (rc == -EINVAL) {
> >
> > Why do you check for -EINVAL only? This way all other errors will be
> > silently ignored.
> 
> Are you sure we must handle other failure codes than -EINVAL here? The called 
> function is very simple and only must distinguish "timeout != 0" and "timeout 
> == 0". So, timeout can be "out of range" or - as you mentioned - some 
> platforms cannot disable the watchdog anymore once it is enabled. Both 
> results into -EINVAL, because the called function cannot use the given value. 
> What else can happen?

Why should we only test for errors that we know and silently drop all others?

Somebody might think that -ENOSYS is the appropriate return value if the
watchdog can't be disabled. When such a patch is added nobody will
remember that our error handling only checks for a special error value.

Sascha


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