ALSA: ice1724 - Check for ac97 to avoid kernel oops

Cards with identical PCI ids but no AC97 config in EEPROM do not have
the ac97 field initialized. We must check for this case to avoid kernel oops.

Signed-off-by: Pavel Hofman <pavel.hofman@ivitera.com>
Cc: <stable@kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/pci/ice1712/amp.c b/sound/pci/ice1712/amp.c
index e328cfb7620c77bd80d1c3788c373f6ababfc520..e525da2673be3c5a4b12de44eb7c81e6ccadfcdd 100644 (file)
--- a/sound/pci/ice1712/amp.c
+++ b/sound/pci/ice1712/amp.c
@@ -68,8 +68,11 @@ static int __devinit snd_vt1724_amp_init(struct snd_ice1712 *ice)
 
 static int __devinit snd_vt1724_amp_add_controls(struct snd_ice1712 *ice)
 {
-       /* we use pins 39 and 41 of the VT1616 for left and right read outputs */
-       snd_ac97_write_cache(ice->ac97, 0x5a, snd_ac97_read(ice->ac97, 0x5a) & ~0x8000);
+       if (ice->ac97)
+               /* we use pins 39 and 41 of the VT1616 for left and right
+               read outputs */
+               snd_ac97_write_cache(ice->ac97, 0x5a,
+                       snd_ac97_read(ice->ac97, 0x5a) & ~0x8000);
        return 0;
 }