ALSA: hda - Fix NULL dereference with enable_beep=0 option

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

sound/pci/hda/patch_sigmatel.c

@@ -3779,15 +3779,16 @@ static int stac92xx_parse_auto_config(struct hda_codec *codec, hda_nid_t dig_out
 		err = snd_hda_attach_beep_device(codec, nid);
 		if (err < 0)
 			return err;
-		/* IDT/STAC codecs have linear beep tone parameter */
-		codec->beep->linear_tone = 1;
-		/* if no beep switch is available, make its own one */
-		caps = query_amp_caps(codec, nid, HDA_OUTPUT);
-		if (codec->beep &&
-		    !((caps & AC_AMPCAP_MUTE) >> AC_AMPCAP_MUTE_SHIFT)) {
-			err = stac92xx_beep_switch_ctl(codec);
-			if (err < 0)
-				return err;
+		if (codec->beep) {
+			/* IDT/STAC codecs have linear beep tone parameter */
+			codec->beep->linear_tone = 1;
+			/* if no beep switch is available, make its own one */
+			caps = query_amp_caps(codec, nid, HDA_OUTPUT);
+			if (!(caps & AC_AMPCAP_MUTE)) {
+				err = stac92xx_beep_switch_ctl(codec);
+				if (err < 0)
+					return err;
+			}
 		}
 	}
 #endif