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From: Dan Carpenter <error27@gmail.com>
To: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: Jarod Wilson <jarod@redhat.com>,
	linux-media@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: [patch -next] V4L/DVB: IR/streamzap: fix usec to nsec conversion
Date: Tue, 12 Oct 2010 08:01:11 +0200	[thread overview]
Message-ID: <20101012060110.GA13176@bicker> (raw)

There is an integer overflow here because 0x03000000 * 1000 is too large
for 31 bits.

rawir.duration should be in terms of nsecs.
IR_MAX_DURATION and 0x03000000 are already in terms of nsecs.
STREAMZAP_TIMEOUT and STREAMZAP_RESOLUTION are 255 and 256 respectively
and are in terms of usecs.

The original code had a deadline of 1.005 seconds and the new code has a
deadline of .065 seconds. 

Signed-off-by: Dan Carpenter <error27@gmail.com>

diff --git a/drivers/media/IR/streamzap.c b/drivers/media/IR/streamzap.c
index 2cf57e6..d5d3cee 100644
--- a/drivers/media/IR/streamzap.c
+++ b/drivers/media/IR/streamzap.c
@@ -221,7 +221,7 @@ static void streamzap_callback(struct urb *urb)
 	struct streamzap_ir *sz;
 	unsigned int i;
 	int len;
-	static int timeout = (((STREAMZAP_TIMEOUT * STREAMZAP_RESOLUTION) &
+	static int timeout = (((STREAMZAP_TIMEOUT * STREAMZAP_RESOLUTION * 1000) &
 				IR_MAX_DURATION) | 0x03000000);
 
 	if (!urb)
@@ -273,7 +273,7 @@ static void streamzap_callback(struct urb *urb)
 				struct ir_raw_event rawir;
 
 				rawir.pulse = false;
-				rawir.duration = timeout * 1000;
+				rawir.duration = timeout;
 				sz->idle = true;
 				if (sz->timeout_enabled)
 					sz_push(sz, rawir);

             reply	other threads:[~2010-10-12  6:01 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-12  6:01 Dan Carpenter [this message]
2010-10-12 13:12 ` [patch -next] V4L/DVB: IR/streamzap: fix usec to nsec conversion Jarod Wilson

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