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-rw-r--r--lib/Kconfig.debug55
1 files changed, 55 insertions, 0 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index aa81d28..31d784d 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -807,6 +807,61 @@ menuconfig BUILD_DOCSRC
Say N if you are unsure.
+config DYNAMIC_PRINTK_DEBUG
+ bool "Enable dynamic printk() call support"
+ default n
+ depends on PRINTK
+ select PRINTK_DEBUG
+ help
+
+ Compiles debug level messages into the kernel, which would not
+ otherwise be available at runtime. These messages can then be
+ enabled/disabled on a per module basis. 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%.
+
+ Usage:
+
+ Dynamic debugging is controlled by the debugfs file,
+ dynamic_printk/modules. This file contains a list of the modules that
+ can be enabled. The format of the file is the module name, followed
+ by a set of flags that can be enabled. The first flag is always the
+ 'enabled' flag. For example:
+
+ <module_name> <enabled=0/1>
+ .
+ .
+ .
+
+ <module_name> : Name of the module in which the debug call resides
+ <enabled=0/1> : whether the messages are enabled or not
+
+ From a live system:
+
+ snd_hda_intel enabled=0
+ fixup enabled=0
+ driver enabled=0
+
+ Enable a module:
+
+ $echo "set enabled=1 <module_name>" > dynamic_printk/modules
+
+ Disable a module:
+
+ $echo "set enabled=0 <module_name>" > dynamic_printk/modules
+
+ Enable all modules:
+
+ $echo "set enabled=1 all" > dynamic_printk/modules
+
+ Disable all modules:
+
+ $echo "set enabled=0 all" > dynamic_printk/modules
+
+ Finally, passing "dynamic_printk" at the command line enables
+ debugging for all modules. This mode can be turned off via the above
+ disable command.
+
source "samples/Kconfig"
source "lib/Kconfig.kgdb"
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