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authorJason Baron <jbaron@redhat.com>2008-08-12 16:46:19 -0400
committerGreg Kroah-Hartman <gregkh@suse.de>2008-10-16 09:24:47 -0700
commit346e15beb5343c2eb8216d820f2ed8f150822b08 (patch)
tree6433cf2980bbfbed4a9482c5edb156fc8371e071 /lib/Kconfig.debug
parent33376c1c043c05077b4ac79c33804266f6c45e49 (diff)
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driver core: basic infrastructure for per-module dynamic debug messages
Base infrastructure to enable per-module debug messages. I've introduced CONFIG_DYNAMIC_PRINTK_DEBUG, which when enabled centralizes control of debugging statements on a per-module basis in one /proc file, currently, <debugfs>/dynamic_printk/modules. When, CONFIG_DYNAMIC_PRINTK_DEBUG, is not set, debugging statements can still be enabled as before, often by defining 'DEBUG' for the proper compilation unit. Thus, this patch set has no affect when CONFIG_DYNAMIC_PRINTK_DEBUG is not set. The infrastructure currently ties into all pr_debug() and dev_dbg() calls. That is, if CONFIG_DYNAMIC_PRINTK_DEBUG is set, all pr_debug() and dev_dbg() calls can be dynamically enabled/disabled on a per-module basis. Future plans include extending this functionality to subsystems, that define their own debug levels and flags. Usage: Dynamic debugging is controlled by the debugfs file, <debugfs>/dynamic_printk/modules. This file contains a list of the modules that can be enabled. The format of the file is as follows: <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 For example: snd_hda_intel enabled=0 fixup enabled=1 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. [gkh: minor cleanups and tweaks to make the build work quietly] Signed-off-by: Jason Baron <jbaron@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'lib/Kconfig.debug')
-rw-r--r--lib/Kconfig.debug55
1 files changed, 55 insertions, 0 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index aa81d284844..31d784dd80d 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"