ALSA: hda - Don't check capture source mixer if no ADC is available

With multiple codec configurations, some codec might have no ADC, thus
it keeps spec->adc_nids = NULL.  This causes an Oops in alc_build_controls().

Reference: kernel bug #16156
	https://bugzilla.kernel.org/show_bug.cgi?id=16156

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

diff --git a/sound/pci/hda/patch_realtek.c b/sound/pci/hda/patch_realtek.c
index fc767b6b4785df50cabd947ddc3174a8d13d5978..f6cd8ed3272f4017faff8b35274ee8f178c47904 100644 (file)
--- a/sound/pci/hda/patch_realtek.c
+++ b/sound/pci/hda/patch_realtek.c
@@ -2619,16 +2619,18 @@ static int alc_build_controls(struct hda_codec *codec)
        }
 
        /* assign Capture Source enums to NID */
-       kctl = snd_hda_find_mixer_ctl(codec, "Capture Source");
-       if (!kctl)
-               kctl = snd_hda_find_mixer_ctl(codec, "Input Source");
-       for (i = 0; kctl && i < kctl->count; i++) {
-               hda_nid_t *nids = spec->capsrc_nids;
-               if (!nids)
-                       nids = spec->adc_nids;
-               err = snd_hda_add_nid(codec, kctl, i, nids[i]);
-               if (err < 0)
-                       return err;
+       if (spec->capsrc_nids || spec->adc_nids) {
+               kctl = snd_hda_find_mixer_ctl(codec, "Capture Source");
+               if (!kctl)
+                       kctl = snd_hda_find_mixer_ctl(codec, "Input Source");
+               for (i = 0; kctl && i < kctl->count; i++) {
+                       hda_nid_t *nids = spec->capsrc_nids;
+                       if (!nids)
+                               nids = spec->adc_nids;
+                       err = snd_hda_add_nid(codec, kctl, i, nids[i]);
+                       if (err < 0)
+                               return err;
+               }
        }
        if (spec->cap_mixer) {
                const char *kname = kctl ? kctl->id.name : NULL;