ipv4: add __rcu annotations to ip_ra_chain

[linux-2.6-block.git] / Documentation / dynamic-debug-howto.txt

diff --git a/Documentation/dynamic-debug-howto.txt b/Documentation/dynamic-debug-howto.txt
index 674c5663d34696bcbc50354eb9edf556def41ef0..58ea64a961653b92e42c6fb384014dc18f250f84 100644 (file)
--- a/Documentation/dynamic-debug-howto.txt
+++ b/Documentation/dynamic-debug-howto.txt
@@ -24,7 +24,7 @@ Dynamic debug has even more useful features:
    read to display the complete list of known debug statements, to help guide you
 
 Controlling dynamic debug Behaviour
    read to display the complete list of known debug statements, to help guide you
 
 Controlling dynamic debug Behaviour

-===============================
+===================================

 
 The behaviour of pr_debug()/dev_debug()s are controlled via writing to a
 control file in the 'debugfs' filesystem. Thus, you must first mount the debugfs
 
 The behaviour of pr_debug()/dev_debug()s are controlled via writing to a
 control file in the 'debugfs' filesystem. Thus, you must first mount the debugfs


@@ -212,6 +212,26 @@ Note the regexp ^[-+=][scp]+$ matches a flags specification.
 Note also that there is no convenient syntax to remove all
 the flags at once, you need to use "-psc".
 
 Note also that there is no convenient syntax to remove all
 the flags at once, you need to use "-psc".
 

+
+Debug messages during boot process
+==================================
+
+To be able to activate debug messages during the boot process,
+even before userspace and debugfs exists, use the boot parameter:
+ddebug_query="QUERY"
+
+QUERY follows the syntax described above, but must not exceed 1023
+characters. The enablement of debug messages is done as an arch_initcall.
+Thus you can enable debug messages in all code processed after this
+arch_initcall via this boot parameter.
+On an x86 system for example ACPI enablement is a subsys_initcall and
+ddebug_query="file ec.c +p"
+will show early Embedded Controller transactions during ACPI setup if
+your machine (typically a laptop) has an Embedded Controller.
+PCI (or other devices) initialization also is a hot candidate for using
+this boot parameter for debugging purposes.
+
+

 Examples
 ========
 
 Examples
 ========