linux-kernel - blink driver power saving

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Message-ID: <20070701125035.3f54d8b0@oldman>
Date:	Sun, 1 Jul 2007 12:50:35 -0400
From:	Stephen Hemminger <shemminger@...ux-foundation.org>
To:	Linus Torvalds <torvalds@...ux-foundation.org>,
	Andrew Morton <akpm@...l.org>, Andi Kleen <ak@...e.de>
Cc:	linux-kernel@...r.kernel.org
Subject: blink driver power saving

The blink driver wakes up every jiffies which wastes power unnecessarily.
Using a notifier gives same effect. Also add ability to unload module.

Signed-off-by: Stephen Hemminger <shemminger@...ux-foundation.org>

--- a/drivers/misc/blink.c	2007-06-29 22:56:20.000000000 -0400
+++ b/drivers/misc/blink.c	2007-07-01 12:44:37.000000000 -0400
@@ -16,12 +16,30 @@ static void do_blink(unsigned long data)
 	add_timer(&blink_timer);
 }
 
-static int blink_init(void)
+static int blink_panic_event(struct notifier_block *blk,
+			     unsigned long event, void *arg)
 {
-	printk(KERN_INFO "Enabling keyboard blinking\n");
 	do_blink(0);
 	return 0;
 }
 
+static struct notifier_block blink_notify = {
+	.notifier_call = blink_panic_event,
+};
+
+static __init int blink_init(void)
+{
+	printk(KERN_INFO "Enabling keyboard blinking\n");
+	atomic_notifier_chain_register(&panic_notifier_list, &blink_notify);
+	return 0;
+}
+
+static __exit void blink_remove(void)
+{
+	del_timer_sync(&blink_timer);
+	atomic_notifier_chain_unregister(&panic_notifier_list, &blink_notify);
+}
+
 module_init(blink_init);
+module_exit(blink_remove);
 
-
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