1 files changed, 85 insertions, 32 deletions

diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
index dc68709e7569..1ec3fd4c8940 100644
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -58,6 +58,7 @@ static int position_fix[SNDRV_CARDS];
 static int probe_mask[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS-1)] = -1};
 static int single_cmd;
 static int enable_msi;
+static int bdl_pos_adj = 1;
 
 module_param_array(index, int, NULL, 0444);
 MODULE_PARM_DESC(index, "Index value for Intel HD audio interface.");
@@ -77,6 +78,8 @@ MODULE_PARM_DESC(single_cmd, "Use single command to communicate with codecs "
                  "(for debugging only).");
 module_param(enable_msi, int, 0444);
 MODULE_PARM_DESC(enable_msi, "Enable Message Signaled Interrupt (MSI)");
+module_param(bdl_pos_adj, int, 0644);
+MODULE_PARM_DESC(bdl_pos_adj, "BDL position adjustment offset");
 
 #ifdef CONFIG_SND_HDA_POWER_SAVE
 /* power_save option is defined in hda_codec.c */
@@ -309,7 +312,8 @@ struct azx_dev {
 
         unsigned int opened :1;
         unsigned int running :1;
-        unsigned int irq_pending: 1;
+        unsigned int irq_pending :1;
+        unsigned int irq_ignore :1;
 };
 
 /* CORB/RIRB */
@@ -943,6 +947,11 @@ static irqreturn_t azx_interrupt(int irq, void *dev_id)
                         azx_sd_writeb(azx_dev, SD_STS, SD_INT_MASK);
                         if (!azx_dev->substream || !azx_dev->running)
                                 continue;
+                        /* ignore the first dummy IRQ (due to pos_adj) */
+                        if (azx_dev->irq_ignore) {
+                                azx_dev->irq_ignore = 0;
+                                continue;
+                        }
                         /* check whether this IRQ is really acceptable */
                         if (azx_position_ok(chip, azx_dev)) {
                                 azx_dev->irq_pending = 0;
@@ -977,14 +986,53 @@ static irqreturn_t azx_interrupt(int irq, void *dev_id)
 
 
 /*
+ * set up a BDL entry
+ */
+static int setup_bdle(struct snd_pcm_substream *substream,
+                      struct azx_dev *azx_dev, u32 **bdlp,
+                      int ofs, int size, int with_ioc)
+{
+        struct snd_sg_buf *sgbuf = snd_pcm_substream_sgbuf(substream);
+        u32 *bdl = *bdlp;
+
+        while (size > 0) {
+                dma_addr_t addr;
+                int chunk;
+
+                if (azx_dev->frags >= AZX_MAX_BDL_ENTRIES)
+                        return -EINVAL;
+
+                addr = snd_pcm_sgbuf_get_addr(sgbuf, ofs);
+                /* program the address field of the BDL entry */
+                bdl[0] = cpu_to_le32((u32)addr);
+                bdl[1] = cpu_to_le32(upper_32bit(addr));
+                /* program the size field of the BDL entry */
+                chunk = PAGE_SIZE - (ofs % PAGE_SIZE);
+                if (size < chunk)
+                        chunk = size;
+                bdl[2] = cpu_to_le32(chunk);
+                /* program the IOC to enable interrupt
+                 * only when the whole fragment is processed
+                 */
+                size -= chunk;
+                bdl[3] = (size || !with_ioc) ? 0 : cpu_to_le32(0x01);
+                bdl += 4;
+                azx_dev->frags++;
+                ofs += chunk;
+        }
+        *bdlp = bdl;
+        return ofs;
+}
+
+/*
  * set up BDL entries
  */
 static int azx_setup_periods(struct snd_pcm_substream *substream,
                              struct azx_dev *azx_dev)
 {
-        struct snd_sg_buf *sgbuf = snd_pcm_substream_sgbuf(substream);
         u32 *bdl;
         int i, ofs, periods, period_bytes;
+        int pos_adj = 0;
 
         /* reset BDL address */
         azx_sd_writel(azx_dev, SD_BDLPL, 0);
@@ -998,39 +1046,44 @@ static int azx_setup_periods(struct snd_pcm_substream *substream,
         bdl = (u32 *)azx_dev->bdl.area;
         ofs = 0;
         azx_dev->frags = 0;
-        for (i = 0; i < periods; i++) {
-                int size, rest;
-                if (i >= AZX_MAX_BDL_ENTRIES) {
-                        snd_printk(KERN_ERR "Too many BDL entries: "
-                                   "buffer=%d, period=%d\n",
-                                   azx_dev->bufsize, period_bytes);
-                        /* reset */
-                        azx_sd_writel(azx_dev, SD_BDLPL, 0);
-                        azx_sd_writel(azx_dev, SD_BDLPU, 0);
-                        return -EINVAL;
+        azx_dev->irq_ignore = 0;
+        if (bdl_pos_adj > 0) {
+                struct snd_pcm_runtime *runtime = substream->runtime;
+                pos_adj = (bdl_pos_adj * runtime->rate + 47999) / 48000;
+                if (!pos_adj)
+                        pos_adj = 1;
+                pos_adj = frames_to_bytes(runtime, pos_adj);
+                if (pos_adj >= period_bytes) {
+                        snd_printk(KERN_WARNING "Too big adjustment %d\n",
+                                   bdl_pos_adj);
+                        pos_adj = 0;
+                } else {
+                        ofs = setup_bdle(substream, azx_dev,
+                                         &bdl, ofs, pos_adj, 1);
+                        if (ofs < 0)
+                                goto error;
+                        azx_dev->irq_ignore = 1;
                 }
-                rest = period_bytes;
-                do {
-                        dma_addr_t addr = snd_pcm_sgbuf_get_addr(sgbuf, ofs);
-                        /* program the address field of the BDL entry */
-                        bdl[0] = cpu_to_le32((u32)addr);
-                        bdl[1] = cpu_to_le32(upper_32bit(addr));
-                        /* program the size field of the BDL entry */
-                        size = PAGE_SIZE - (ofs % PAGE_SIZE);
-                        if (rest < size)
-                                size = rest;
-                        bdl[2] = cpu_to_le32(size);
-                        /* program the IOC to enable interrupt
-                         * only when the whole fragment is processed
-                         */
-                        rest -= size;
-                        bdl[3] = rest ? 0 : cpu_to_le32(0x01);
-                        bdl += 4;
-                        azx_dev->frags++;
-                        ofs += size;
-                } while (rest > 0);
+        }
+        for (i = 0; i < periods; i++) {
+                if (i == periods - 1 && pos_adj)
+                        ofs = setup_bdle(substream, azx_dev, &bdl, ofs,
+                                         period_bytes - pos_adj, 0);
+                else
+                        ofs = setup_bdle(substream, azx_dev, &bdl, ofs,
+                                         period_bytes, 1);
+                if (ofs < 0)
+                        goto error;
         }
         return 0;
+
+ error:
+        snd_printk(KERN_ERR "Too many BDL entries: buffer=%d, period=%d\n",
+                   azx_dev->bufsize, period_bytes);
+        /* reset */
+        azx_sd_writel(azx_dev, SD_BDLPL, 0);
+        azx_sd_writel(azx_dev, SD_BDLPU, 0);
+        return -EINVAL;
 }
 
 /*