[ALSA] ac97 - Fix silent output problem with Cx20551 codec

Fixed the silent output problem on laptops with Conexant Cx20551 codec
chip, such as Packard-bell EasyNote A* series.
The information was taken from ALSA bug#1134.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

sound/pci/ac97/ac97_codec.c

@@ -143,6 +143,7 @@ static const struct ac97_codec_id snd_ac97_codec_ids[] = {
 { 0x43525970, 0xfffffff8, "CS4202",		NULL,		NULL },
 { 0x43585421, 0xffffffff, "HSD11246",		NULL,		NULL },	// SmartMC II
 { 0x43585428, 0xfffffff8, "Cx20468",		patch_conexant,	NULL }, // SmartAMC fixme: the mask might be different
+{ 0x43585431, 0xffffffff, "Cx20551",           patch_cx20551,  NULL },
 { 0x44543031, 0xfffffff0, "DT0398",		NULL,		NULL },
 { 0x454d4328, 0xffffffff, "EM28028",		NULL,		NULL },  // same as TR28028?
 { 0x45838308, 0xffffffff, "ESS1988",		NULL,		NULL },

sound/pci/ac97/ac97_patch.c

@@ -1338,6 +1338,12 @@ int patch_conexant(struct snd_ac97 * ac97)
 	return 0;
 }
 
+int patch_cx20551(struct snd_ac97 *ac97)
+{
+	snd_ac97_update_bits(ac97, 0x5c, 0x01, 0x01);
+	return 0;
+}
+
 /*
  * Analog Device AD18xx, AD19xx codecs
  */

sound/pci/ac97/ac97_patch.h

@@ -39,6 +39,7 @@ int patch_sigmatel_stac9758(struct snd_ac97 * ac97);
 int patch_cirrus_cs4299(struct snd_ac97 * ac97);
 int patch_cirrus_spdif(struct snd_ac97 * ac97);
 int patch_conexant(struct snd_ac97 * ac97);
+int patch_cx20551(struct snd_ac97 * ac97);
 int patch_ad1819(struct snd_ac97 * ac97);
 int patch_ad1881(struct snd_ac97 * ac97);
 int patch_ad1885(struct snd_ac97 * ac97);