Messages in this thread | | | Date | Thu, 19 Jan 2012 12:33:27 +0300 | From | Dan Carpenter <> | Subject | Re: [patch 2/2] [media] ds3000: off by one in ds3000_read_snr() |
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On Wed, Jan 18, 2012 at 06:06:46PM +0100, walter harms wrote: > > > Am 17.01.2012 08:30, schrieb Dan Carpenter: > > This is a static checker patch and I don't have the hardware to test > > this, so please review it carefully. The dvbs2_snr_tab[] array has 80 > > elements so when we cap it at 80, that's off by one. I would have > > assumed that the test was wrong but in the lines right before we have > > the same test but use "snr_reading - 1" as the array offset. I've done > > the same thing here. > > > > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> > > > > diff --git a/drivers/media/dvb/frontends/ds3000.c b/drivers/media/dvb/frontends/ds3000.c > > index af65d01..3f5ae0a 100644 > > --- a/drivers/media/dvb/frontends/ds3000.c > > +++ b/drivers/media/dvb/frontends/ds3000.c > > @@ -681,7 +681,7 @@ static int ds3000_read_snr(struct dvb_frontend *fe, u16 *snr) > > snr_reading = dvbs2_noise_reading / tmp; > > if (snr_reading > 80) > > snr_reading = 80; > > - *snr = -(dvbs2_snr_tab[snr_reading] / 1000); > > + *snr = -(dvbs2_snr_tab[snr_reading - 1] / 1000); > > } > > dprintk("%s: raw / cooked = 0x%02x / 0x%04x\n", __func__, > > snr_reading, *snr); > > hi dan, > > perhaps it is more useful to do it in the check above ?
It looks like the check is correct but we need to shift all the values by one. Again, I don't have this hardware, I'm just going by the context.
> thinking about that why not replace the number (80) with ARRAY_SIZE() ?
That would be a cleanup, yes but it could go in a separate patch.
regards, dan carpenter
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