From: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
Date: Thu, 20 May 2010 21:47:52 +0000 (-0400)
Subject: Using udelay to busy wait for about 10 seconds.
X-Git-Url: http://git.cascardo.eti.br/?a=commitdiff_plain;h=refs%2Fheads%2Ftime;hp=014bb573eed1a3f9c907a4ae6186834e98dbb85c;p=cascardo%2Fkernel%2Fsamples%2Fchar2%2F.git

Using udelay to busy wait for about 10 seconds.
---

diff --git a/hellochar.c b/hellochar.c
index a197a1d..7f659f5 100644
--- a/hellochar.c
+++ b/hellochar.c
@@ -39,9 +39,9 @@ static int hello_open(struct inode *ino, struct file *fp)
 static ssize_t hello_read(struct file *fp, char __user *buf, size_t sz,
 	loff_t *pos)
 {
-	unsigned long expire = jiffies + 5 * HZ;
-	while (time_after(expire, jiffies))
-		cpu_relax();
+	int i = 1 << 20;
+	while (i--)
+		udelay(10);
 	return 0;
 }