ALSA: hda - Fix VIA recording problem

Add a workaround for bad DMA-position reporting on VIA chipset.

Signed-off-by: Joseph Chan <josephchan@via.com.tw>
[modified and cleaned up by tiwai]
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>

1 files changed, 88 insertions, 3 deletions

diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
index 4f80248837e..52a3adfac7f 100644
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -286,6 +286,11 @@ enum {
 #define INTEL_SCH_HDA_DEVC      0x78
 #define INTEL_SCH_HDA_DEVC_NOSNOOP       (0x1<<11)
 
+/* Define IN stream 0 FIFO size offset in VIA controller */
+#define VIA_IN_STREAM0_FIFO_SIZE_OFFSET 0x90
+/* Define VIA HD Audio Device ID*/
+#define VIA_HDAC_DEVICE_ID              0x3288
+
 
 /*
  */
@@ -317,6 +322,12 @@ struct azx_dev {
         unsigned int running :1;
         unsigned int irq_pending :1;
         unsigned int irq_ignore :1;
+        /*
+         * For VIA:
+         *  A flag to ensure DMA position is 0
+         *  when link position is not greater than FIFO size
+         */
+        unsigned int insufficient :1;
 };
 
 /* CORB/RIRB */
@@ -379,6 +390,7 @@ struct azx {
         unsigned int polling_mode :1;
         unsigned int msi :1;
         unsigned int irq_pending_warned :1;
+        unsigned int via_dmapos_patch :1; /* enable DMA-position fix for VIA */
 
         /* for debugging */
         unsigned int last_cmd;  /* last issued command (to sync) */
@@ -818,6 +830,11 @@ static void azx_int_clear(struct azx *chip)
 /* start a stream */
 static void azx_stream_start(struct azx *chip, struct azx_dev *azx_dev)
 {
+        /*
+         * Before stream start, initialize parameter
+         */
+        azx_dev->insufficient = 1;
+
         /* enable SIE */
         azx_writeb(chip, INTCTL,
                    azx_readb(chip, INTCTL) | (1 << azx_dev->index));
@@ -1148,7 +1165,8 @@ static int azx_setup_controller(struct azx *chip, struct azx_dev *azx_dev)
 
         /* enable the position buffer */
         if (chip->position_fix == POS_FIX_POSBUF ||
-            chip->position_fix == POS_FIX_AUTO) {
+            chip->position_fix == POS_FIX_AUTO ||
+            chip->via_dmapos_patch) {
                 if (!(azx_readl(chip, DPLBASE) & ICH6_DPLBASE_ENABLE))
                         azx_writel(chip, DPLBASE,
                                 (u32)chip->posbuf.addr | ICH6_DPLBASE_ENABLE);
@@ -1504,13 +1522,71 @@ static int azx_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
         return 0;
 }
 
+/* get the current DMA position with correction on VIA chips */
+static unsigned int azx_via_get_position(struct azx *chip,
+                                         struct azx_dev *azx_dev)
+{
+        unsigned int link_pos, mini_pos, bound_pos;
+        unsigned int mod_link_pos, mod_dma_pos, mod_mini_pos;
+        unsigned int fifo_size;
+
+        link_pos = azx_sd_readl(azx_dev, SD_LPIB);
+        if (azx_dev->index >= 4) {
+                /* Playback, no problem using link position */
+                return link_pos;
+        }
+
+        /* Capture */
+        /* For new chipset,
+         * use mod to get the DMA position just like old chipset
+         */
+        mod_dma_pos = le32_to_cpu(*azx_dev->posbuf);
+        mod_dma_pos %= azx_dev->period_bytes;
+
+        /* azx_dev->fifo_size can't get FIFO size of in stream.
+         * Get from base address + offset.
+         */
+        fifo_size = readw(chip->remap_addr + VIA_IN_STREAM0_FIFO_SIZE_OFFSET);
+
+        if (azx_dev->insufficient) {
+                /* Link position never gather than FIFO size */
+                if (link_pos <= fifo_size)
+                        return 0;
+
+                azx_dev->insufficient = 0;
+        }
+
+        if (link_pos <= fifo_size)
+                mini_pos = azx_dev->bufsize + link_pos - fifo_size;
+        else
+                mini_pos = link_pos - fifo_size;
+
+        /* Find nearest previous boudary */
+        mod_mini_pos = mini_pos % azx_dev->period_bytes;
+        mod_link_pos = link_pos % azx_dev->period_bytes;
+        if (mod_link_pos >= fifo_size)
+                bound_pos = link_pos - mod_link_pos;
+        else if (mod_dma_pos >= mod_mini_pos)
+                bound_pos = mini_pos - mod_mini_pos;
+        else {
+                bound_pos = mini_pos - mod_mini_pos + azx_dev->period_bytes;
+                if (bound_pos >= azx_dev->bufsize)
+                        bound_pos = 0;
+        }
+
+        /* Calculate real DMA position we want */
+        return bound_pos + mod_dma_pos;
+}
+
 static unsigned int azx_get_position(struct azx *chip,
                                      struct azx_dev *azx_dev)
 {
         unsigned int pos;
 
-        if (chip->position_fix == POS_FIX_POSBUF ||
-            chip->position_fix == POS_FIX_AUTO) {
+        if (chip->via_dmapos_patch)
+                pos = azx_via_get_position(chip, azx_dev);
+        else if (chip->position_fix == POS_FIX_POSBUF ||
+                 chip->position_fix == POS_FIX_AUTO) {
                 /* use the position buffer */
                 pos = le32_to_cpu(*azx_dev->posbuf);
         } else {
@@ -1946,6 +2022,15 @@ static int __devinit check_position_fix(struct azx *chip, int fix)
 {
         const struct snd_pci_quirk *q;
 
+        /* Check VIA HD Audio Controller exist */
+        if (chip->pci->vendor == PCI_VENDOR_ID_VIA &&
+            chip->pci->device == VIA_HDAC_DEVICE_ID) {
+                chip->via_dmapos_patch = 1;
+                /* Use link position directly, avoid any transfer problem. */
+                return POS_FIX_LPIB;
+        }
+        chip->via_dmapos_patch = 0;
+
         if (fix == POS_FIX_AUTO) {
                 q = snd_pci_quirk_lookup(chip->pci, position_fix_list);
                 if (q) {