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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Stephen Rothwell <sfr@canb.auug.org.au>,
        Johannes Berg <johannes@sipsolutions.net>,
        Takashi Iwai <tiwai@suse.de>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.9 175/271] ALSA: aoa: onyx: always initialize register read value
Date:   Tue, 28 Jan 2020 15:05:24 +0100
Message-Id: <20200128135905.583232508@linuxfoundation.org>
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From: Johannes Berg <johannes@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@canb.auug.org.au>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@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 a04edff8b729e..ae50d59fb810f 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