ALSA: oxygen: prevent muting of nonexistent AC97 controls

The Xonar DX does not have CD Capture controls, so we have to check that
a control actually exists before muting it.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Cc: <stable@kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 4 insertions, 1 deletions

diff --git a/sound/pci/oxygen/oxygen_mixer.c b/sound/pci/oxygen/oxygen_mixer.c
index 6facac5aed90..05eb8994c141 100644
--- a/sound/pci/oxygen/oxygen_mixer.c
+++ b/sound/pci/oxygen/oxygen_mixer.c
@@ -512,9 +512,12 @@ static int ac97_switch_get(struct snd_kcontrol *ctl,
 
 static void mute_ac97_ctl(struct oxygen *chip, unsigned int control)
 {
-        unsigned int priv_idx = chip->controls[control]->private_value & 0xff;
+        unsigned int priv_idx;
         u16 value;
 
+        if (!chip->controls[control])
+                return;
+        priv_idx = chip->controls[control]->private_value & 0xff;
         value = oxygen_read_ac97(chip, 0, priv_idx);
         if (!(value & 0x8000)) {
                 oxygen_write_ac97(chip, 0, priv_idx, value | 0x8000);