ALSA: hda/realtek - Fix possible Oops with NULL input_mux

When BIOS is damn crazy and gives no pin-config at all, the driver might
lead to a NULL dereference.  Let's add a NULL check for such a case.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 3 insertions, 0 deletions

diff --git a/sound/pci/hda/patch_realtek.c b/sound/pci/hda/patch_realtek.c
index eba50dff6130..997cc8127a08 100644
--- a/sound/pci/hda/patch_realtek.c
+++ b/sound/pci/hda/patch_realtek.c
@@ -302,6 +302,9 @@ static int alc_mux_select(struct hda_codec *codec, unsigned int adc_idx,
         int i, type, num_conns;
         hda_nid_t nid;
 
+        if (!spec->input_mux)
+                return 0;
+
         mux_idx = adc_idx >= spec->num_mux_defs ? 0 : adc_idx;
         imux = &spec->input_mux[mux_idx];
         if (!imux->num_items && mux_idx > 0)