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>

diff --git a/sound/pci/oxygen/oxygen_mixer.c b/sound/pci/oxygen/oxygen_mixer.c
index 6facac5aed90b3cddcb26bdf444098d84b5e09ad..05eb8994c141a899966a5f9ce791b1fa0ef28343 100644 (file)
--- 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);