Merge ../torvalds-2.6/

[cascardo/linux.git] / Documentation / sysrq.txt

diff --git a/Documentation/sysrq.txt b/Documentation/sysrq.txt
index f98c2e3..baf17b3 100644 (file)
--- a/Documentation/sysrq.txt
+++ b/Documentation/sysrq.txt
@@ -72,6 +72,8 @@ On all -  write a character to /proc/sysrq-trigger.  eg:
 'b'     - Will immediately reboot the system without syncing or unmounting
           your disks.
 
+'c'    - Will perform a kexec reboot in order to take a crashdump.
+
 'o'     - Will shut your system off (if configured and supported).
 
 's'     - Will attempt to sync all mounted filesystems.
@@ -122,6 +124,9 @@ useful when you want to exit a program that will not let you switch consoles.
 re'B'oot is good when you're unable to shut down. But you should also 'S'ync
 and 'U'mount first.
 
+'C'rashdump can be used to manually trigger a crashdump when the system is hung.
+The kernel needs to have been built with CONFIG_KEXEC enabled.
+
 'S'ync is great when your system is locked up, it allows you to sync your
 disks and will certainly lessen the chance of data loss and fscking. Note
 that the sync hasn't taken place until you see the "OK" and "Done" appear
@@ -166,7 +171,7 @@ the header 'include/linux/sysrq.h', this will define everything else you need.
 Next, you must create a sysrq_key_op struct, and populate it with A) the key
 handler function you will use, B) a help_msg string, that will print when SysRQ
 prints help, and C) an action_msg string, that will print right before your
-handler is called. Your handler must conform to the protoype in 'sysrq.h'.
+handler is called. Your handler must conform to the prototype in 'sysrq.h'.
 
 After the sysrq_key_op is created, you can call the macro 
 register_sysrq_key(int key, struct sysrq_key_op *op_p) that is defined in