media: ts2020: avoid integer overflows on 32 bit machines

Before this patch, when compiled for arm32, the signal strength
were reported as:

Lock   (0x1f) Signal= 4294908.66dBm C/N= 12.79dB

Because of a 32 bit integer overflow. After it, it is properly
reported as:

	Lock   (0x1f) Signal= -58.64dBm C/N= 12.79dB

Cc: stable@vger.kernel.org
Fixes: 0f91c9d6ba ("[media] TS2020: Calculate tuner gain correctly")
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
This commit is contained in:
Mauro Carvalho Chehab 2018-01-10 07:20:39 -05:00
parent 4852fdca88
commit 81742be14b

View File

@ -368,7 +368,7 @@ static int ts2020_read_tuner_gain(struct dvb_frontend *fe, unsigned v_agc,
gain2 = clamp_t(long, gain2, 0, 13);
v_agc = clamp_t(long, v_agc, 400, 1100);
*_gain = -(gain1 * 2330 +
*_gain = -((__s64)gain1 * 2330 +
gain2 * 3500 +
v_agc * 24 / 10 * 10 +
10000);
@ -386,7 +386,7 @@ static int ts2020_read_tuner_gain(struct dvb_frontend *fe, unsigned v_agc,
gain3 = clamp_t(long, gain3, 0, 6);
v_agc = clamp_t(long, v_agc, 600, 1600);
*_gain = -(gain1 * 2650 +
*_gain = -((__s64)gain1 * 2650 +
gain2 * 3380 +
gain3 * 2850 +
v_agc * 176 / 100 * 10 -