[PATCH] pm_trace is dangerous

CONFIG_PM_TRACES scrogs your RTC.  Mark it as experimental, and defaulting to
`off'.

Also beef up the help message a bit.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 11 insertions, 2 deletions

diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index fc311a4673a2..857b4fa09124 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -38,13 +38,22 @@ config PM_DEBUG
 
 config PM_TRACE
         bool "Suspend/resume event tracing"
-        depends on PM && PM_DEBUG && X86_32
-        default y
+        depends on PM && PM_DEBUG && X86_32 && EXPERIMENTAL
+        default n
         ---help---
         This enables some cheesy code to save the last PM event point in the
         RTC across reboots, so that you can debug a machine that just hangs
         during suspend (or more commonly, during resume).
 
+        To use this debugging feature you should attempt to suspend the machine,
+        then reboot it, then run
+
+                dmesg -s 1000000 | grep 'hash matches'
+
+        CAUTION: this option will cause your machine's real-time clock to be
+        set to an invalid time after a resume.
+
+
 config SOFTWARE_SUSPEND
         bool "Software Suspend"
         depends on PM && SWAP && (X86 && (!SMP || SUSPEND_SMP)) || ((FRV || PPC32) && !SMP)