Messages in this thread | | | Date | Tue, 4 Mar 2014 14:39:42 +0100 | Subject | Re: [PATCH 1/1] Add documentation for proper usage and order of preference of calls to print diagnostic messages. | From | Levente Kurusa <> |
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Hi,
2014-03-04 12:48 GMT+01:00 yogesh <mr.yogesh@gmail.com>: > This patch adds documentation that clarifies the use of various diagnostic printing messages. It shows the preference of subsystem_dbg calls to dev_dbg (whenever possible), as the first preferred format of logging debug messages.
Please wrap your changelog at 80 characters a line.
> Signed-off-by: Yogesh Chaudhari <mr.yogesh@gmail.com> > --- > Documentation/CodingStyle | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) > > diff --git a/Documentation/CodingStyle b/Documentation/CodingStyle > index 7fe0546..9e0de25 100644 > --- a/Documentation/CodingStyle > +++ b/Documentation/CodingStyle > @@ -662,6 +662,20 @@ and driver, and are tagged with the right level: dev_err(), dev_warn(), > dev_info(), and so forth. For messages that aren't associated with a > particular device, <linux/printk.h> defines pr_debug() and pr_info(). > > +If the subsystem has its own diagnostic macros then they should be used > +instead of dev_dbg calls. > +e.g. If you are using network subsystem, use netdev_dbg; > +if you are using V4L, use v4l_dbg etc. > +This standardises the output format in every subsystem. > + > +Depending on your changes, the following order of precedence > +applies to printing messages: > +1. [subsystem]_dbg() is preferred when you the
The 'you' is unnecessary and incorrect.
> +subsystem has its own diagnostic macros. > +2. dev_dbg() is preferred when you have a generic struct device object. > +3. pr_debug() is used when 1 and 2 above are not applicable.
I think it's better to say "should be used".
> +4. printk() should be avoided. > + > Coming up with good debugging messages can be quite a challenge; and once > you have them, they can be a huge help for remote troubleshooting. Such > messages should be compiled out when the DEBUG symbol is not defined (that
I think we should also mention *_warn, *_err etc not just *_dbg.
-- Regards, Levente Kurusa
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