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| author | Olof Johansson <olof@lixom.net> | 2014-07-19 14:59:07 -0700 |
|---|---|---|
| committer | Olof Johansson <olof@lixom.net> | 2014-07-19 14:59:07 -0700 |
| commit | 4e9816d012dbc28dc89559261c6ffbf8ffc440dd (patch) | |
| tree | dee9f8b31f3d6d2fb141541da88e1cc1329b017e /Documentation/CodingStyle | |
| parent | da98f44f27d81d7fe9a41f69af4fe08c18d13b56 (diff) | |
| parent | 1795cd9b3a91d4b5473c97f491d63892442212ab (diff) | |
Merge tag 'v3.16-rc5' into next/fixes-non-critical
Linux 3.16-rc5
Diffstat (limited to 'Documentation/CodingStyle')
| -rw-r--r-- | Documentation/CodingStyle | 22 |
1 files changed, 15 insertions, 7 deletions
diff --git a/Documentation/CodingStyle b/Documentation/CodingStyle index 7fe0546c504..6b6bef31e95 100644 --- a/Documentation/CodingStyle +++ b/Documentation/CodingStyle @@ -660,15 +660,23 @@ There are a number of driver model diagnostic macros in <linux/device.h> which you should use to make sure messages are matched to the right device 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(). +particular device, <linux/printk.h> defines pr_notice(), pr_info(), +pr_warn(), pr_err(), etc. 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 -is, by default they are not included). When you use dev_dbg() or pr_debug(), -that's automatic. Many subsystems have Kconfig options to turn on -DDEBUG. -A related convention uses VERBOSE_DEBUG to add dev_vdbg() messages to the -ones already enabled by DEBUG. +you have them, they can be a huge help for remote troubleshooting. However +debug message printing is handled differently than printing other non-debug +messages. While the other pr_XXX() functions print unconditionally, +pr_debug() does not; it is compiled out by default, unless either DEBUG is +defined or CONFIG_DYNAMIC_DEBUG is set. That is true for dev_dbg() also, +and a related convention uses VERBOSE_DEBUG to add dev_vdbg() messages to +the ones already enabled by DEBUG. + +Many subsystems have Kconfig debug options to turn on -DDEBUG in the +corresponding Makefile; in other cases specific files #define DEBUG. And +when a debug message should be unconditionally printed, such as if it is +already inside a debug-related #ifdef secton, printk(KERN_DEBUG ...) can be +used. Chapter 14: Allocating memory |