On 03/04/2014 06:31 AM, yogesh wrote: > 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 they first preferred format of > logging debug messages. > Signed-off-by: Yogesh Chaudhari <mr.yog...@gmail.com> > --- > Documentation/CodingStyle | 17 +++++++++++++++++ > 1 file changed, 17 insertions(+) > > diff --git a/Documentation/CodingStyle b/Documentation/CodingStyle > index 7fe0546..083f738 100644 > --- a/Documentation/CodingStyle > +++ b/Documentation/CodingStyle > @@ -662,6 +662,23 @@ 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;
E.g., if you are > +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 the subsystem has its own > +diagnostic macros. > +2. dev_dbg() is preferred when you have a generic struct device object. > +3. pr_debug() should be used when 1 and 2 above are not applicable. > +4. printk() should be avoided. > + > +Note: The above order applies to diagnostic calls of all log levels viz: > +*_emerg, *_alert, *_crit, *_err, *_warn, *_notice, *_info and *_dbg. > + > 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 > -- -- ~Randy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
