diff mbox

[-next] V4L/DVB: IR/streamzap: fix usec to nsec conversion

Message ID 20101012060110.GA13176@bicker (mailing list archive)
State Superseded, archived
Headers

Commit Message

Dan Carpenter Oct. 12, 2010, 6:01 a.m. UTC 
  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>

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Comments

Jarod Wilson Oct. 12, 2010, 1:12 p.m. UTC | #1 
On Tue, Oct 12, 2010 at 08:01:11AM +0200, Dan Carpenter wrote:
> 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>

Nice catch, fix looks good.

Acked-by: Jarod Wilson <jarod@redhat.com>
diff mbox

Patch

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);