[PATCH] m88ts2022: fix 32bit overflow on filter calc

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Maximum satellite symbol rate used is 45000000Sps which overflows
when multiplied by 135. As final calculation result is fraction,
we could use mult_frac macro in order to keep calculation inside
32 bit number limits and prevent overflow.

Original bug and fix was provided by Nibble Max. I decided to
implement it differently as it is now.

Reported-by: Nibble Max <nibble.max@xxxxxxxxx>
Cc: <stable@xxxxxxxxxx>
Signed-off-by: Antti Palosaari <crope@xxxxxx>
---
 drivers/media/tuners/m88ts2022.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/tuners/m88ts2022.c b/drivers/media/tuners/m88ts2022.c
index 40c42de..7a62097 100644
--- a/drivers/media/tuners/m88ts2022.c
+++ b/drivers/media/tuners/m88ts2022.c
@@ -314,7 +314,7 @@ static int m88ts2022_set_params(struct dvb_frontend *fe)
 	div_min = gdiv28 * 78 / 100;
 	div_max = clamp_val(div_max, 0U, 63U);
 
-	f_3db_hz = c->symbol_rate * 135UL / 200UL;
+	f_3db_hz = mult_frac(c->symbol_rate, 135, 200);
 	f_3db_hz +=  2000000U + (frequency_offset_khz * 1000U);
 	f_3db_hz = clamp(f_3db_hz, 7000000U, 40000000U);
 
-- 
http://palosaari.fi/

--
To unsubscribe from this list: send the line "unsubscribe linux-media" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [Linux Input]     [Video for Linux]     [Gstreamer Embedded]     [Mplayer Users]     [Linux USB Devel]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [Yosemite Backpacking]
  Powered by Linux