[ALSA] Fix CMI9739A silent problem

AC97 Codec Core
Fix by Zinx Verituse <zinx@epicsol.org>
The patch for cmi9739a is added.  The undocumented unmute bits are
enabled.
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/ac97/ac97_codec.c

@@ -118,6 +118,7 @@ static const ac97_codec_id_t snd_ac97_codec_ids[] = {
 { 0x414c4770, 0xfffffff0, "ALC203",		NULL,		NULL },
 { 0x434d4941, 0xffffffff, "CMI9738",		patch_cm9738,	NULL },
 { 0x434d4961, 0xffffffff, "CMI9739",		patch_cm9739,	NULL },
+{ 0x434d4983, 0xffffffff, "CMI9739A",		patch_cm9739,	NULL },
 { 0x434d4978, 0xffffffff, "CMI9761",		patch_cm9761,	NULL },
 { 0x434d4982, 0xffffffff, "CMI9761",		patch_cm9761,	NULL },
 { 0x434d4983, 0xffffffff, "CMI9761",		patch_cm9761,	NULL },

sound/pci/ac97/ac97_patch.c

@@ -1877,8 +1877,12 @@ int patch_cm9739(ac97_t * ac97)
 	/* bit 12: disable center/lfe (swithable) */
 	/* bit 10: disable surround/line (switchable) */
 	/* bit 9: mix 2 surround off */
+	/* bit 4: undocumented; 0 mutes the CM9739A, which defaults to 1 */
+	/* bit 3: undocumented; surround? */
 	/* bit 0: dB */
-	val = (1 << 13);
+	val = snd_ac97_read(ac97, AC97_CM9739_MULTI_CHAN) & (1 << 4);
+	val |= (1 << 3);
+	val |= (1 << 13);
 	if (! (ac97->ext_id & AC97_EI_SPDIF))
 		val |= (1 << 14);
 	snd_ac97_write_cache(ac97, AC97_CM9739_MULTI_CHAN, val);