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

From: Ben Hutchings
Date: Tue Nov 21 2017 - 22:00:28 EST


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

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

From: Colin Ian King <colin.king@xxxxxxxxxxxxx>

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@xxxxxxxxxxxxx>
Signed-off-by: Hans Verkuil <hansverk@xxxxxxxxx>
Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx>
[bwh: Backported to 3.2: adjust filename]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
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;
}