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From: Alexandre Belloni <alexandre.belloni@free-electrons.com>
To: Joe Perches <joe@perches.com>
Cc: Aaro Koskinen <aaro.koskinen@iki.fi>,
	Alessandro Zummo <a.zummo@towertech.it>,
	rtc-linux@googlegroups.com, linux-kernel@vger.kernel.org
Subject: [rtc-linux] Re: [PATCH 2/3] rtc: __rtc_read_time: reduce log level
Date: Wed, 1 Apr 2015 11:55:01 +0200	[thread overview]
Message-ID: <20150401095501.GS3849@piout.net> (raw)
In-Reply-To: <1427858719.18175.32.camel@perches.com>

On 31/03/2015 at 20:25:19 -0700, Joe Perches wrote :
> 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().
> 

As the issue may be sporadic, I would say that the reasoning behind the
patch is correct. Userspace is already aware that something went wrong
when reading and those debug messages are not adding any information.


-- 
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

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  reply	other threads:[~2015-04-01  9:55 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-28 21:09 [rtc-linux] [PATCH 1/3] rtc: initialize rtc name early Aaro Koskinen
2015-03-28 21:09 ` [rtc-linux] [PATCH 2/3] rtc: __rtc_read_time: reduce log level Aaro Koskinen
2015-04-01  3:21   ` [rtc-linux] " Alexandre Belloni
2015-04-01  3:25     ` Joe Perches
2015-04-01  9:55       ` Alexandre Belloni [this message]
2015-03-28 21:09 ` [rtc-linux] [PATCH 3/3] rtc: hctosys: use function name in the error log Aaro Koskinen
2015-04-01  3:01   ` [rtc-linux] " Alexandre Belloni
2015-04-01  3:18     ` Joe Perches
2015-04-01  7:05       ` Alessandro Zummo
2015-04-01  7:15         ` Joe Perches
2015-04-01 10:42       ` Alexandre Belloni
2015-04-01 16:12         ` [rtc-linux] [PATCH] rtc: Use more standard kernel logging styles Joe Perches
2015-04-02  7:47           ` Krzysztof Kozlowski
2015-04-05 10:17           ` [rtc-linux] " Alexandre Belloni
2015-04-01  3:01 ` [rtc-linux] Re: [PATCH 1/3] rtc: initialize rtc name early Alexandre Belloni

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