Using udelay to busy wait for about 10 seconds.

diff --git a/hellochar.c b/hellochar.c
index a197a1d..7f659f5 100644 (file)
--- 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;
 }