ALSA: hda - Don't reset BDL unnecessarily

So far, the prepare callback is called multiple times, BDL entries
are reset and re-programmed at each time.

This patch adds the check to avoid the reset of BDL entries when the
same parameters are used.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 32 insertions, 14 deletions

diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
index 6bcf5af6edce..ba97795d89c4 100644
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -1076,8 +1076,7 @@ static int azx_setup_periods(struct azx *chip,
         azx_sd_writel(azx_dev, SD_BDLPL, 0);
         azx_sd_writel(azx_dev, SD_BDLPU, 0);
 
-        period_bytes = snd_pcm_lib_period_bytes(substream);
-        azx_dev->period_bytes = period_bytes;
+        period_bytes = azx_dev->period_bytes;
         periods = azx_dev->bufsize / period_bytes;
 
         /* program the initial BDL entries */
@@ -1124,9 +1123,6 @@ static int azx_setup_periods(struct azx *chip,
  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;
 }
 
@@ -1429,6 +1425,11 @@ static int azx_pcm_close(struct snd_pcm_substream *substream)
 static int azx_pcm_hw_params(struct snd_pcm_substream *substream,
                              struct snd_pcm_hw_params *hw_params)
 {
+        struct azx_dev *azx_dev = get_azx_dev(substream);
+
+        azx_dev->bufsize = 0;
+        azx_dev->period_bytes = 0;
+        azx_dev->format_val = 0;
         return snd_pcm_lib_malloc_pages(substream,
                                         params_buffer_bytes(hw_params));
 }
@@ -1443,6 +1444,9 @@ static int azx_pcm_hw_free(struct snd_pcm_substream *substream)
         azx_sd_writel(azx_dev, SD_BDLPL, 0);
         azx_sd_writel(azx_dev, SD_BDLPU, 0);
         azx_sd_writel(azx_dev, SD_CTL, 0);
+        azx_dev->bufsize = 0;
+        azx_dev->period_bytes = 0;
+        azx_dev->format_val = 0;
 
         hinfo->ops.cleanup(hinfo, apcm->codec, substream);
 
@@ -1456,23 +1460,37 @@ static int azx_pcm_prepare(struct snd_pcm_substream *substream)
         struct azx_dev *azx_dev = get_azx_dev(substream);
         struct hda_pcm_stream *hinfo = apcm->hinfo[substream->stream];
         struct snd_pcm_runtime *runtime = substream->runtime;
+        unsigned int bufsize, period_bytes, format_val;
+        int err;
 
-        azx_dev->bufsize = snd_pcm_lib_buffer_bytes(substream);
-        azx_dev->format_val = snd_hda_calc_stream_format(runtime->rate,
-                                                         runtime->channels,
-                                                         runtime->format,
-                                                         hinfo->maxbps);
-        if (!azx_dev->format_val) {
+        format_val = snd_hda_calc_stream_format(runtime->rate,
+                                                runtime->channels,
+                                                runtime->format,
+                                                hinfo->maxbps);
+        if (!format_val) {
                 snd_printk(KERN_ERR SFX
                            "invalid format_val, rate=%d, ch=%d, format=%d\n",
                            runtime->rate, runtime->channels, runtime->format);
                 return -EINVAL;
         }
 
+        bufsize = snd_pcm_lib_buffer_bytes(substream);
+        period_bytes = snd_pcm_lib_period_bytes(substream);
+
         snd_printdd("azx_pcm_prepare: bufsize=0x%x, format=0x%x\n",
-                    azx_dev->bufsize, azx_dev->format_val);
-        if (azx_setup_periods(chip, substream, azx_dev) < 0)
-                return -EINVAL;
+                    bufsize, format_val);
+
+        if (bufsize != azx_dev->bufsize ||
+            period_bytes != azx_dev->period_bytes ||
+            format_val != azx_dev->format_val) {
+                azx_dev->bufsize = bufsize;
+                azx_dev->period_bytes = period_bytes;
+                azx_dev->format_val = format_val;
+                err = azx_setup_periods(chip, substream, azx_dev);
+                if (err < 0)
+                        return err;
+        }
+
         azx_setup_controller(chip, azx_dev);
         if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
                 azx_dev->fifo_size = azx_sd_readw(azx_dev, SD_FIFOSIZE) + 1;