Re: [PATCH 2/3] rtc: __rtc_read_time: reduce log level

From: Joe Perches
Date: Tue Mar 31 2015 - 23:25:27 EST


On Wed, 2015-04-01 at 05:21 +0200, Alexandre Belloni wrote:
> On 28/03/2015 at 23:09:35 +0200, Aaro Koskinen wrote :
> > __rtc_read_time logs should be debug logs instead of error logs.
> >
> > For example, when the RTC clock is not set, it's not really useful
> > to print a kernel error log every time someone tries to read the clock:
> >
> > ~ # hwclock -r
> > [ 604.508263] rtc rtc0: read_time: fail to read
> > hwclock: RTC_RD_TIME: Invalid argument
> >
> > If there's a real error, it's likely that lower level or higher level
> > code will tell it anyway. Make these logs debug logs, and also print
> > the error code for the read failure.
> >
>
> That actually may be the only error message printed for some failures.
> Some RTCs don't print anything in case of error in their .read_time()
> and there are in-kernel users of rtc_read_time that simply bail out
> without printing anything or have a trace that is already at the debug
> level.
>
> I would agree that this would need a better harmonization and I guess we
> can do that for now. I'll try to fix the in-kernel cases.

Maybe these should use dev_err_once().

> > diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
[]
> > @@ -31,13 +31,14 @@ static int __rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm)
> > memset(tm, 0, sizeof(struct rtc_time));
> > err = rtc->ops->read_time(rtc->dev.parent, tm);
> > if (err < 0) {
> > - dev_err(&rtc->dev, "read_time: fail to read\n");
> > + dev_dbg(&rtc->dev, "read_time: fail to read: %d\n",
> > + err);
> > return err;
> > }
> >
> > err = rtc_valid_tm(tm);
> > if (err < 0)
> > - dev_err(&rtc->dev, "read_time: rtc_time isn't valid\n");
> > + dev_dbg(&rtc->dev, "read_time: rtc_time isn't valid\n");
> > }
> > return err;
> > }



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