[ALSA] Add position_fix module option

Documentation,HDA Intel driver
Added position_fix module option to HDA-intel driver for fixing up
the DMA position (possibly hardware-) bugs.
Signed-off-by: Takashi Iwai <tiwai@suse.de>

Documentation/sound/alsa/ALSA-Configuration.txt

@@ -618,6 +618,7 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed.
     Module for Intel HD Audio (ICH6, ICH6M, ICH7)
 
     model	- force the model name
+    position_fix - Fix DMA pointer (0 = FIFO size, 1 = none, 2 = POSBUF)
 
     Module supports up to 8 cards.
 
@@ -643,6 +644,14 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed.
 	  full_dig	6-jack in back, 2-jack in front, SPDIF I/O
 	  allout	5-jack in back, 2-jack in front, SPDIF out
 
+    Note 2: If you get click noises on output, try the module option
+	    position_fix=1 or 2.  position_fix=1 will use the SD_LPIB
+	    register value without FIFO size correction as the current
+	    DMA pointer.  position_fix=2 will make the driver to use
+	    the position buffer instead of reading SD_LPIB register.
+	    (Usually SD_LPLIB register is more accurate than the
+	    position buffer.)
+
   Module snd-hdsp
   ---------------
 

sound/pci/hda/hda_intel.c

@@ -51,6 +51,7 @@ static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;
 static int enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE_PNP;
 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;
 static char *model[SNDRV_CARDS];
+static int position_fix[SNDRV_CARDS];
 
 module_param_array(index, int, NULL, 0444);
 MODULE_PARM_DESC(index, "Index value for Intel HD audio interface.");
@@ -60,6 +61,8 @@ module_param_array(enable, bool, NULL, 0444);
 MODULE_PARM_DESC(enable, "Enable Intel HD audio interface.");
 module_param_array(model, charp, NULL, 0444);
 MODULE_PARM_DESC(model, "Use the given board model.");
+module_param_array(position_fix, bool, NULL, 0444);
+MODULE_PARM_DESC(position_fix, "Fix DMA pointer (0 = FIFO size, 1 = none, 2 = POSBUF).");
 
 MODULE_LICENSE("GPL");
 MODULE_SUPPORTED_DEVICE("{{Intel, ICH6},"
@@ -183,6 +186,12 @@ enum { SDI0, SDI1, SDI2, SDI3, SDO0, SDO1, SDO2, SDO3 };
 #define ICH6_MAX_CORB_ENTRIES	256
 #define ICH6_MAX_RIRB_ENTRIES	256
 
+/* position fix mode */
+enum {
+	POS_FIX_FIFO,
+	POS_FIX_NONE,
+	POS_FIX_POSBUF
+};
 
 /*
  * Use CORB/RIRB for communication from/to codecs.
@@ -190,12 +199,6 @@ enum { SDI0, SDI1, SDI2, SDI3, SDO0, SDO1, SDO2, SDO3 };
  */
 #define USE_CORB_RIRB
 
-/*
- * Define this if use the position buffer instead of reading SD_LPIB
- * It's not used as default since SD_LPIB seems to give more accurate position
- */
-/* #define USE_POSBUF */
-
 /*
  */
 
@@ -271,6 +274,9 @@ struct snd_azx {
 	struct snd_dma_buffer bdl;
 	struct snd_dma_buffer rb;
 	struct snd_dma_buffer posbuf;
+
+	/* flags */
+	int position_fix;
 };
 
 /*
@@ -657,11 +663,11 @@ static void azx_init_chip(azx_t *chip)
 	/* initialize the codec command I/O */
 	azx_init_cmd_io(chip);
 
-#ifdef USE_POSBUF
+	if (chip->position_fix == POS_FIX_POSBUF) {
 		/* program the position buffer */
 		azx_writel(chip, DPLBASE, (u32)chip->posbuf.addr);
 		azx_writel(chip, DPUBASE, upper_32bit(chip->posbuf.addr));
-#endif
+	}
 }
 
 
@@ -791,11 +797,12 @@ static int azx_setup_controller(azx_t *chip, azx_dev_t *azx_dev)
 	/* upper BDL address */
 	azx_sd_writel(azx_dev, SD_BDLPU, upper_32bit(azx_dev->bdl_addr));
 
-#ifdef USE_POSBUF
+	if (chip->position_fix == POS_FIX_POSBUF) {
 		/* enable the position buffer */
 		if (! (azx_readl(chip, DPLBASE) & ICH6_DPLBASE_ENABLE))
 			azx_writel(chip, DPLBASE, (u32)chip->posbuf.addr | ICH6_DPLBASE_ENABLE);
-#endif
+	}
+
 	/* set the interrupt enable bits in the descriptor control register */
 	azx_sd_writel(azx_dev, SD_CTL, azx_sd_readl(azx_dev, SD_CTL) | SD_INT_MASK);
 
@@ -1036,16 +1043,20 @@ static int azx_pcm_trigger(snd_pcm_substream_t *substream, int cmd)
 
 static snd_pcm_uframes_t azx_pcm_pointer(snd_pcm_substream_t *substream)
 {
+	struct azx_pcm *apcm = snd_pcm_substream_chip(substream);
+	azx_t *chip = apcm->chip;
 	azx_dev_t *azx_dev = get_azx_dev(substream);
 	unsigned int pos;
 
-#ifdef USE_POSBUF
+	if (chip->position_fix == POS_FIX_POSBUF) {
 		/* use the position buffer */
 		pos = *azx_dev->posbuf;
-#else
+	} else {
 		/* read LPIB */
-	pos = azx_sd_readl(azx_dev, SD_LPIB) + azx_dev->fifo_size;
-#endif
+		pos = azx_sd_readl(azx_dev, SD_LPIB);
+		if (chip->position_fix == POS_FIX_FIFO)
+			pos += azx_dev->fifo_size;
+	}
 	if (pos >= azx_dev->bufsize)
 		pos = 0;
 	return bytes_to_frames(substream->runtime, pos);
@@ -1155,9 +1166,8 @@ static int __devinit azx_init_stream(azx_t *chip)
 		azx_dev_t *azx_dev = &chip->azx_dev[i];
 		azx_dev->bdl = (u32 *)(chip->bdl.area + off);
 		azx_dev->bdl_addr = chip->bdl.addr + off;
-#ifdef USE_POSBUF
+		if (chip->position_fix == POS_FIX_POSBUF)
 			azx_dev->posbuf = (volatile u32 *)(chip->posbuf.area + i * 8);
-#endif
 		/* offset: SDI0=0x80, SDI1=0xa0, ... SDO3=0x160 */
 		azx_dev->sd_addr = chip->remap_addr + (0x20 * i + 0x80);
 		/* int mask: SDI0=0x01, SDI1=0x02, ... SDO3=0x80 */
@@ -1237,10 +1247,8 @@ static int azx_free(azx_t *chip)
 		snd_dma_free_pages(&chip->bdl);
 	if (chip->rb.area)
 		snd_dma_free_pages(&chip->rb);
-#ifdef USE_POSBUF
 	if (chip->posbuf.area)
 		snd_dma_free_pages(&chip->posbuf);
-#endif
 	pci_release_regions(chip->pci);
 	pci_disable_device(chip->pci);
 	kfree(chip);
@@ -1256,7 +1264,8 @@ static int azx_dev_free(snd_device_t *device)
 /*
  * constructor
  */
-static int __devinit azx_create(snd_card_t *card, struct pci_dev *pci, azx_t **rchip)
+static int __devinit azx_create(snd_card_t *card, struct pci_dev *pci,
+				int posfix, azx_t **rchip)
 {
 	azx_t *chip;
 	int err = 0;
@@ -1283,6 +1292,8 @@ static int __devinit azx_create(snd_card_t *card, struct pci_dev *pci, azx_t **r
 	chip->pci = pci;
 	chip->irq = -1;
 
+	chip->position_fix = posfix;
+
 	if ((err = pci_request_regions(pci, "ICH HD audio")) < 0) {
 		kfree(chip);
 		pci_disable_device(pci);
@@ -1314,14 +1325,14 @@ static int __devinit azx_create(snd_card_t *card, struct pci_dev *pci, azx_t **r
 		snd_printk(KERN_ERR SFX "cannot allocate BDL\n");
 		goto errout;
 	}
-#ifdef USE_POSBUF
+	if (chip->position_fix == POS_FIX_POSBUF) {
 		/* allocate memory for the position buffer */
 		if ((err = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, snd_dma_pci_data(chip->pci),
 					       MAX_ICH6_DEV * 8, &chip->posbuf)) < 0) {
 			snd_printk(KERN_ERR SFX "cannot allocate posbuf\n");
 			goto errout;
 		}
-#endif
+	}
 	/* allocate CORB/RIRB */
 	if ((err = azx_alloc_cmd_io(chip)) < 0)
 		goto errout;
@@ -1372,7 +1383,7 @@ static int __devinit azx_probe(struct pci_dev *pci, const struct pci_device_id *
 		return -ENOMEM;
 	}
 
-	if ((err = azx_create(card, pci, &chip)) < 0) {
+	if ((err = azx_create(card, pci, position_fix[dev], &chip)) < 0) {
 		snd_card_free(card);
 		return err;
 	}