forked from pool/rtl-sdr
41 lines
1.3 KiB
Diff
41 lines
1.3 KiB
Diff
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From d794155ba65796a76cd0a436f9709f4601509320 Mon Sep 17 00:00:00 2001
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From: Derrick Pallas <derrick@pallas.us>
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Date: Wed, 18 Mar 2020 14:54:48 -0700
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Subject: [PATCH] tuner_r82xx: fix short-write in r82xx_read
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In r82xx_read, there is a 1-byte I2C write followed by the I2C read. If
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this I2C write fails, r82xx_read correctly bails out but may return 0.
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Callers that check whether (rc < 0) will assume that the buffer was written
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when it has not been, e.g. in r82xx_set_tv_standard where
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priv->fil_cal_code = data[4] & 0x0f;
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consumes a garbage value for data[4].
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This change resolves that issue by copying the error path from r82xx_write.
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---
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src/tuner_r82xx.c | 10 ++++++++--
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1 file changed, 8 insertions(+), 2 deletions(-)
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diff --git a/src/tuner_r82xx.c b/src/tuner_r82xx.c
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index fe52bd9..997abd7 100644
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--- a/src/tuner_r82xx.c
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+++ b/src/tuner_r82xx.c
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@@ -330,8 +330,14 @@ static int r82xx_read(struct r82xx_priv *priv, uint8_t reg, uint8_t *val, int le
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priv->buf[0] = reg;
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rc = rtlsdr_i2c_write_fn(priv->rtl_dev, priv->cfg->i2c_addr, priv->buf, 1);
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- if (rc < 1)
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- return rc;
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+
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+ if (rc != 1) {
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+ fprintf(stderr, "%s: i2c wr failed=%d reg=%02x len=%d\n",
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+ __FUNCTION__, rc, reg, 1);
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+ if (rc < 0)
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+ return rc;
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+ return -1;
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+ }
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rc = rtlsdr_i2c_read_fn(priv->rtl_dev, priv->cfg->i2c_addr, p, len);
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