[ALSA] cs4281 - fix DLLRDY not seen problem

CS4281 driver
Reset the FPDN bit of the EPPMC register if needed.
Signed-off-by: Arnaud Patard <arnaud.patard@rtp-net.org>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

sound/pci/cs4281.c

@@ -206,7 +206,10 @@ MODULE_PARM_DESC(dual_codec, "Secondary Codec ID (0 = disabled).");
 
 #define BA0_PMCS		0x0344	/* Power Management Control/Status */
 #define BA0_CWPR		0x03e0	/* Configuration Write Protect */
+
 #define BA0_EPPMC		0x03e4	/* Extended PCI Power Management Control */
+#define BA0_EPPMC_FPDN		(1<<14) /* Full Power DowN */
+
 #define BA0_GPIOR		0x03e8	/* GPIO Pin Interface Register */
 
 #define BA0_SPMC		0x03ec	/* Serial Port Power Management Control (& ASDIN2 enable) */
@@ -1461,6 +1464,11 @@ static int snd_cs4281_chip_init(cs4281_t *chip)
 	int timeout;
 	int retry_count = 2;
 
+	/* Having EPPMC.FPDN=1 prevent proper chip initialisation */
+	tmp = snd_cs4281_peekBA0(chip, BA0_EPPMC);
+	if (tmp & BA0_EPPMC_FPDN)
+		snd_cs4281_pokeBA0(chip, BA0_EPPMC, tmp & ~BA0_EPPMC_FPDN);
+
       __retry:
 	tmp = snd_cs4281_peekBA0(chip, BA0_CFLR);
 	if (tmp != BA0_CFLR_DEFAULT) {