[alsa-devel] [PATCH AUTOSEL 4.9 174/251] ALSA: aoa: onyx: always initialize register read value

[Sasha Levin]

From: Johannes Berg <johannes at sipsolutions.net>

[ Upstream commit f474808acb3c4b30552d9c59b181244e0300d218 ]

A lot of places in the driver use onyx_read_register() without
checking the return value, and it's been working OK for ~10 years
or so, so probably never fails ... Rather than trying to check the
return value everywhere, which would be relatively intrusive, at
least make sure we don't use an uninitialized value.

Fixes: f3d9478b2ce4 ("[ALSA] snd-aoa: add snd-aoa")
Reported-by: Stephen Rothwell <sfr at canb.auug.org.au>
Signed-off-by: Johannes Berg <johannes at sipsolutions.net>
Signed-off-by: Takashi Iwai <tiwai at suse.de>
Signed-off-by: Sasha Levin <sashal at kernel.org>
---
 sound/aoa/codecs/onyx.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/sound/aoa/codecs/onyx.c b/sound/aoa/codecs/onyx.c
index a04edff8b729..ae50d59fb810 100644
--- a/sound/aoa/codecs/onyx.c
+++ b/sound/aoa/codecs/onyx.c
@@ -74,8 +74,10 @@ static int onyx_read_register(struct onyx *onyx, u8 reg, u8 *value)
 		return 0;
 	}
 	v = i2c_smbus_read_byte_data(onyx->i2c, reg);
-	if (v < 0)
+	if (v < 0) {
+		*value = 0;
 		return -1;
+	}
 	*value = (u8)v;
 	onyx->cache[ONYX_REG_CONTROL-FIRSTREGISTER] = *value;
 	return 0;
-- 
2.20.1