doc: Clarify that nmi_watchdog param is for hardlockups

The kernel NMI watchdog acts as both a hardlockup and softlockup detector.
However, the kernel parameter nmi_watchdog can only enable or disable the
hardlockup detector. Clarify that in the documentation.

Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 7a01cc0b0b312258ec8c826afbc3a5fcb1b4c3ce..f97071ac9b4ce70ba944e0ec08a30a769a583718 100644 (file)
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2320,11 +2320,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
        nmi_watchdog=   [KNL,BUGS=X86] Debugging features for SMP kernels
                        Format: [panic,][nopanic,][num]
                        Valid num: 0 or 1
-                       0 - turn nmi_watchdog off
-                       1 - turn nmi_watchdog on
+                       0 - turn hardlockup detector in nmi_watchdog off
+                       1 - turn hardlockup detector in nmi_watchdog on
                        When panic is specified, panic when an NMI watchdog
                        timeout occurs (or 'nopanic' to override the opposite
-                       default).
+                       default). To disable both hard and soft lockup detectors,
+                       please see 'nowatchdog'.
                        This is useful when you use a panic=... timeout and
                        need the box quickly up again.