dib7000p_read_word() may return zero on i2c errors, resulting in
dib7000p_get_internal_freq() returning zero.
So don't divide by the result of dib7000p_get_internal_freq()
without checking it for zero in dib7000p_set_dds().
On one of my machines the device
ID 2304:0229 Pinnacle Systems, Inc. PCTV Dual DVB-T 2001e
about once a day/every two days gets into a state, where
most (all?) I2C reads return with an error. Tuning during this
state will result in a divide by zero without this patch.
This patch doesn't fix the root cause for the device getting
into a bad state, but it allows me to unload/reload the drivers,
bringing it back into a usable state.
Signed-off-by: Martin Wache <m.wa...@gmx.net>
---
drivers/media/dvb-frontends/dib7000p.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/drivers/media/dvb-frontends/dib7000p.c
b/drivers/media/dvb-frontends/dib7000p.c
index a27c000..3815ea5 100644
--- a/drivers/media/dvb-frontends/dib7000p.c
+++ b/drivers/media/dvb-frontends/dib7000p.c
@@ -805,13 +805,19 @@ static int dib7000p_set_agc_config(struct dib7000p_state
*state, u8 band)
return 0;
}
-static void dib7000p_set_dds(struct dib7000p_state *state, s32 offset_khz)
+static int dib7000p_set_dds(struct dib7000p_state *state, s32 offset_khz)
{
u32 internal = dib7000p_get_internal_freq(state);
- s32 unit_khz_dds_val = 67108864 / (internal); /* 2**26 / Fsampling is
the unit 1KHz offset */
+ s32 unit_khz_dds_val;
u32 abs_offset_khz = ABS(offset_khz);
u32 dds = state->cfg.bw->ifreq & 0x1ffffff;
u8 invert = !!(state->cfg.bw->ifreq & (1 << 25));
+ if (internal == 0) {
+ pr_warn("DIB7000P: dib7000p_get_internal_freq returned 0\n");
+ return -1;
+ }
+ /* 2**26 / Fsampling is the unit 1KHz offset */
+ unit_khz_dds_val = 67108864 / (internal);
dprintk("setting a frequency offset of %dkHz internal freq = %d invert
= %d\n", offset_khz, internal, invert);
@@ -828,6 +834,7 @@ static void dib7000p_set_dds(struct dib7000p_state *state,
s32 offset_khz)
dib7000p_write_word(state, 21, (u16) (((dds >> 16) & 0x1ff) |
(0 << 10) | (invert << 9)));
dib7000p_write_word(state, 22, (u16) (dds & 0xffff));
}
+ return 0;
}
static int dib7000p_agc_startup(struct dvb_frontend *demod)
@@ -867,7 +874,9 @@ static int dib7000p_agc_startup(struct dvb_frontend *demod)
frequency_offset = (s32)frequency_tuner / 1000 -
ch->frequency / 1000;
}
- dib7000p_set_dds(state, frequency_offset);
+ if (dib7000p_set_dds(state, frequency_offset) < 0)
+ return -1;
+
ret = 7;
(*agc_state)++;
break;
--
2.7.4
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