[PATCH 4.19 043/264] media: tuner-simple: fix regression in simple_set_radio_freq

Greg Kroah-Hartman
2020-10-27T14:21:57Z

From: Tom Rix <trix@redhat.com>

[ Upstream commit 505bfc2a142f12ce7bc7a878b44abc3496f2e747 ]

clang static analysis reports this problem

tuner-simple.c:714:13: warning: Assigned value is
garbage or undefined
buffer[1] = buffer[3];
^ ~~~~~~~~~
In simple_set_radio_freq buffer[3] used to be done
in-function with a switch of tuner type, now done
by a call to simple_radio_bandswitch which has this case

case TUNER_TENA_9533_DI:
case TUNER_YMEC_TVF_5533MF:
tuner_dbg("This tuner doesn't ...
return 0;

which does not set buffer[3]. In the old logic, this case
would have returned 0 from simple_set_radio_freq.

Recover this old behavior by returning an error for this
codition. Since the old simple_set_radio_freq behavior
returned a 0, do the same.

Fixes: c7a9f3aa1e1b ("V4L/DVB (7129): tuner-simple: move device-specific code into three separate functions")
Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/media/tuners/tuner-simple.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/media/tuners/tuner-simple.c b/drivers/media/tuners/tuner-simple.c
index 29c1473f2e9f6..81e24cf0c8b80 100644
--- a/drivers/media/tuners/tuner-simple.c
+++ b/drivers/media/tuners/tuner-simple.c
@@ -499,7 +499,7 @@ static int simple_radio_bandswitch(struct dvb_frontend *fe, u8 *buffer)
case TUNER_TENA_9533_DI:
case TUNER_YMEC_TVF_5533MF:
tuner_dbg("This tuner doesn't have FM. Most cards have a TEA5767 for FM\n");
- return 0;
+ return -EINVAL;
case TUNER_PHILIPS_FM1216ME_MK3:
case TUNER_PHILIPS_FM1236_MK3:
case TUNER_PHILIPS_FMD1216ME_MK3:
@@ -701,7 +701,8 @@ static int simple_set_radio_freq(struct dvb_frontend *fe,
TUNER_RATIO_SELECT_50; /* 50 kHz step */

/* Bandswitch byte */
- simple_radio_bandswitch(fe, &buffer[0]);
+ if (simple_radio_bandswitch(fe, &buffer[0]))
+ return 0;

/* Convert from 1/16 kHz V4L steps to 1/20 MHz (=50 kHz) PLL steps
freq * (1 Mhz / 16000 V4L steps) * (20 PLL steps / 1 MHz) =
--
2.25.1