[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>

diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index fc311a4673a25e451e94c1eef38c00bc425acf5a..857b4fa091244758b5fc0976cf44d58f914f20ec 100644 (file)
--- 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)