1 files changed, 21 insertions, 12 deletions

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 6777153f18f..e1193417703 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -3,12 +3,16 @@ config PRINTK_TIME
         bool "Show timing information on printks"
         depends on PRINTK
         help
-          Selecting this option causes timing information to be
-          included in printk output.  This allows you to measure
-          the interval between kernel operations, including bootup
-          operations.  This is useful for identifying long delays
-          in kernel startup.  Or add printk.time=1 at boot-time.
-          See Documentation/kernel-parameters.txt
+          Selecting this option causes time stamps of the printk()
+          messages to be added to the output of the syslog() system
+          call and at the console.
+
+          The timestamp is always recorded internally, and exported
+          to /dev/kmsg. This flag just specifies if the timestamp should
+          be included, not that the timestamp is recorded.
+
+          The behavior is also controlled by the kernel command line
+          parameter printk.time=1. See Documentation/kernel-parameters.txt
 
 config DEFAULT_MESSAGE_LOGLEVEL
         int "Default message log level (1-7)"
@@ -1205,8 +1209,13 @@ config DYNAMIC_DEBUG
           otherwise be available at runtime. These messages can then be
           enabled/disabled based on various levels of scope - per source file,
           function, module, format string, and line number. This mechanism
-          implicitly enables all pr_debug() and dev_dbg() calls. The impact of
-          this compile option is a larger kernel text size of about 2%.
+          implicitly compiles in all pr_debug() and dev_dbg() calls, which
+          enlarges the kernel text size by about 2%.
+
+          If a source file is compiled with DEBUG flag set, any
+          pr_debug() calls in it are enabled by default, but can be
+          disabled at runtime as below.  Note that DEBUG flag is
+          turned on by many CONFIG_*DEBUG* options.
 
           Usage:
 
@@ -1223,16 +1232,16 @@ config DYNAMIC_DEBUG
           lineno : line number of the debug statement
           module : module that contains the debug statement
           function : function that contains the debug statement
-          flags : 'p' means the line is turned 'on' for printing
+          flags : '=p' means the line is turned 'on' for printing
           format : the format used for the debug statement
 
           From a live system:
 
                 nullarbor:~ # cat <debugfs>/dynamic_debug/control
                 # filename:lineno [module]function flags format
-                fs/aio.c:222 [aio]__put_ioctx - "__put_ioctx:\040freeing\040%p\012"
-                fs/aio.c:248 [aio]ioctx_alloc - "ENOMEM:\040nr_events\040too\040high\012"
-                fs/aio.c:1770 [aio]sys_io_cancel - "calling\040cancel\012"
+                fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
+                fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
+                fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
 
           Example usage: