PM: Optional beeping during resume from suspend to RAM

Add a feature allowing the user to make the system beep during a resume from
suspend to RAM, on x86_64 and i386.

This is useful for the users with broken resume from RAM, so that they can
verify if the control reaches the kernel after a wake-up event.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 23 insertions, 0 deletions

diff --git a/kernel/power/main.c b/kernel/power/main.c
index 32147b57c3bf..c74a56436d8b 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -332,6 +332,27 @@ static ssize_t state_store(struct kset *kset, const char *buf, size_t n)
 
 power_attr(state);
 
+unsigned long s2ram_beep = 0;
+
+static ssize_t s2ram_beep_show(struct kset *kset, char *buf)
+{
+        return sprintf(buf, "%d\n", s2ram_beep);
+}
+
+static ssize_t
+s2ram_beep_store(struct kset *kset, const char *buf, size_t n)
+{
+        int val;
+
+        if (sscanf(buf, "%d", &val) > 0) {
+                s2ram_beep = val;
+                return n;
+        }
+        return -EINVAL;
+}
+
+power_attr(s2ram_beep);
+
 #ifdef CONFIG_PM_TRACE
 int pm_trace_enabled;
 
@@ -357,11 +378,13 @@ power_attr(pm_trace);
 static struct attribute * g[] = {
         &state_attr.attr,
         &pm_trace_attr.attr,
+        &s2ram_beep_attr.attr,
         NULL,
 };
 #else
 static struct attribute * g[] = {
         &state_attr.attr,
+        &s2ram_beep_attr.attr,
         NULL,
 };
 #endif /* CONFIG_PM_TRACE */