[PATCH] PM: Add pm_trace switch

Add the pm_trace attribute in /sys/power which has to be explicitly set to
one to really enable the "PM tracing" code compiled in when CONFIG_PM_TRACE
is set (which modifies the machine's CMOS clock in unpredictable ways).

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 14 insertions, 10 deletions

diff --git a/include/linux/resume-trace.h b/include/linux/resume-trace.h
index a376bd4ade39..81e9299ca148 100644
--- a/include/linux/resume-trace.h
+++ b/include/linux/resume-trace.h
@@ -3,21 +3,25 @@
 
 #ifdef CONFIG_PM_TRACE
 
+extern int pm_trace_enabled;
+
 struct device;
 extern void set_trace_device(struct device *);
 extern void generate_resume_trace(void *tracedata, unsigned int user);
 
 #define TRACE_DEVICE(dev) set_trace_device(dev)
-#define TRACE_RESUME(user) do {                         \
-        void *tracedata;                                \
-        asm volatile("movl $1f,%0\n"                    \
-                ".section .tracedata,\"a\"\n"           \
-                "1:\t.word %c1\n"                       \
-                "\t.long %c2\n"                         \
-                ".previous"                             \
-                :"=r" (tracedata)                       \
-                : "i" (__LINE__), "i" (__FILE__));      \
-        generate_resume_trace(tracedata, user);         \
+#define TRACE_RESUME(user) do {                                 \
+        if (pm_trace_enabled) {                                 \
+                void *tracedata;                                \
+                asm volatile("movl $1f,%0\n"                    \
+                        ".section .tracedata,\"a\"\n"           \
+                        "1:\t.word %c1\n"                       \
+                        "\t.long %c2\n"                         \
+                        ".previous"                             \
+                        :"=r" (tracedata)                       \
+                        : "i" (__LINE__), "i" (__FILE__));      \
+                generate_resume_trace(tracedata, user);         \
+        }                                                       \
 } while (0)
 
 #else