linux-kernel - [PATCH 3.2 21/61] media: em28xx: calculate left volume level correctly

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Message-ID: <lsq.1511316666.618321691@decadent.org.uk>
Date:   Wed, 22 Nov 2017 02:11:06 +0000
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, "Hans Verkuil" <hansverk@...co.com>,
        "Colin Ian King" <colin.king@...onical.com>,
        "Mauro Carvalho Chehab" <mchehab@...pensource.com>
Subject: [PATCH 3.2 21/61] media: em28xx: calculate left volume level
 correctly

3.2.96-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Colin Ian King <colin.king@...onical.com>

commit 801e3659bf2c87c31b7024087d61e89e172b5651 upstream.

The calculation of the left volume looks suspect, the value of
0x1f - ((val << 8) & 0x1f) is always 0x1f. The debug prior to the
assignment of value[1] prints the left volume setting using the
calculation 0x1f - (val >> 8) & 0x1f which looks correct to me.
Fix the left volume by using the correct expression as used in
the debug.

Detected by CoverityScan, CID#146140 ("Wrong operator used")

Fixes: 850d24a5a861 ("[media] em28xx-alsa: add mixer support for AC97 volume controls")

Signed-off-by: Colin Ian King <colin.king@...onical.com>
Signed-off-by: Hans Verkuil <hansverk@...co.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@...pensource.com>
[bwh: Backported to 3.2: adjust filename]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 drivers/media/video/em28xx/em28xx-audio.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/media/video/em28xx/em28xx-audio.c
+++ b/drivers/media/video/em28xx/em28xx-audio.c
@@ -507,7 +507,7 @@ static int em28xx_vol_get(struct snd_kco
 		val, (int)kcontrol->private_value);
 
 	value->value.integer.value[0] = 0x1f - (val & 0x1f);
-	value->value.integer.value[1] = 0x1f - ((val << 8) & 0x1f);
+	value->value.integer.value[1] = 0x1f - ((val >> 8) & 0x1f);
 
 	return 0;
 }