ALSA: opl3sa2 - Fix NULL dereference when suspending snd_opl3sa2

Fix the OOPS during a opl3sa2 card suspend
and resume if the driver is loaded but the card
is not found.

Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Cc: <stable@kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 12 insertions, 6 deletions

diff --git a/sound/isa/opl3sa2.c b/sound/isa/opl3sa2.c
index 58c972b2af03..b848d1001864 100644
--- a/sound/isa/opl3sa2.c
+++ b/sound/isa/opl3sa2.c
@@ -550,21 +550,27 @@ static int __devinit snd_opl3sa2_mixer(struct snd_card *card)
 #ifdef CONFIG_PM
 static int snd_opl3sa2_suspend(struct snd_card *card, pm_message_t state)
 {
-        struct snd_opl3sa2 *chip = card->private_data;
+        if (card) {
+                struct snd_opl3sa2 *chip = card->private_data;
 
-        snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
-        chip->wss->suspend(chip->wss);
-        /* power down */
-        snd_opl3sa2_write(chip, OPL3SA2_PM_CTRL, OPL3SA2_PM_D3);
+                snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
+                chip->wss->suspend(chip->wss);
+                /* power down */
+                snd_opl3sa2_write(chip, OPL3SA2_PM_CTRL, OPL3SA2_PM_D3);
+        }
 
         return 0;
 }
 
 static int snd_opl3sa2_resume(struct snd_card *card)
 {
-        struct snd_opl3sa2 *chip = card->private_data;
+        struct snd_opl3sa2 *chip;
         int i;
 
+        if (!card)
+                return 0;
+
+        chip = card->private_data;
         /* power up */
         snd_opl3sa2_write(chip, OPL3SA2_PM_CTRL, OPL3SA2_PM_D0);