Em Sat, 16 Aug 2014 14:12:32 +0800 "nibble.max" <nibble.max@xxxxxxxxx> escreveu: > The current m88ts2022 driver will miss the following high symbol rate transponders on Telstar 18 138.0. > 12385 H 43200, > 12690 H 43200, > 12538 V 41250... > the code for f_3db_hz will overflow for the high symbol rate. > for example, symbol rate=41250 KS/s > symbol_rate * 135UL = 5568750000(1 4BEC 61B0), the value is larger than unsigned int on 32bit platform. > that makes the wrong result. > Exchanging the div and mul position fixs it. > > Signed-off-by: Nibble Max <nibble.max@xxxxxxxxx> > --- > 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..65c8acc 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 = (c->symbol_rate / 200UL) * 135UL; Hmm... wouldn't this make worse for low symbol rates? IMHO, the better is to use a u64 instead, and do_div64(). > f_3db_hz += 2000000U + (frequency_offset_khz * 1000U); > f_3db_hz = clamp(f_3db_hz, 7000000U, 40000000U); > Regards, -- Cheers, Mauro -- 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
