ALSA: hda - Add Kconfig for the default buffer size

Add a Kconfig entry to specify the default buffer size.
Distros using PulseAudio can choose a larger value here.

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

2 files changed, 20 insertions, 1 deletions

diff --git a/sound/pci/hda/Kconfig b/sound/pci/hda/Kconfig
index 70762fca57ee..1f1a4ae4b791 100644
--- a/sound/pci/hda/Kconfig
+++ b/sound/pci/hda/Kconfig
@@ -14,6 +14,19 @@ menuconfig SND_HDA_INTEL
 
 if SND_HDA_INTEL
 
+config SND_HDA_PREALLOC_SIZE
+        int "Pre-allocated buffer size for HD-audio driver"
+        range 0 32768
+        default 64
+        help
+          Speficies the default pre-allocated buffer-size in kB for
+          HD-audio driver.  A larger buffer (e.g. 2048) is preferred
+          for systems with PulseAudio.  The default 64 is chosen just
+          from the compatibility reason.
+
+          Note that the pre-allocation size can be changed dynamically
+          via a proc file (/proc/asound/card*/pcm*/sub*/prealloc), too.
+
 config SND_HDA_HWDEP
         bool "Build hwdep interface for HD-audio driver"
         select SND_HWDEP
diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
index 25619cd18831..5ce9531cba67 100644
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -2075,6 +2075,8 @@ static void azx_pcm_free(struct snd_pcm *pcm)
         }
 }
 
+#define MAX_PREALLOC_SIZE       (32 * 1024 * 1024)
+
 static int
 azx_attach_pcm_stream(struct hda_bus *bus, struct hda_codec *codec,
                       struct hda_pcm *cpcm)
@@ -2083,6 +2085,7 @@ azx_attach_pcm_stream(struct hda_bus *bus, struct hda_codec *codec,
         struct snd_pcm *pcm;
         struct azx_pcm *apcm;
         int pcm_dev = cpcm->device;
+        unsigned int size;
         int s, err;
 
         if (pcm_dev >= HDA_MAX_PCMS) {
@@ -2118,9 +2121,12 @@ azx_attach_pcm_stream(struct hda_bus *bus, struct hda_codec *codec,
                         snd_pcm_set_ops(pcm, s, &azx_pcm_ops);
         }
         /* buffer pre-allocation */
+        size = CONFIG_SND_HDA_PREALLOC_SIZE * 1024;
+        if (size > MAX_PREALLOC_SIZE)
+                size = MAX_PREALLOC_SIZE;
         snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_DEV_SG,
                                               snd_dma_pci_data(chip->pci),
-                                              1024 * 64, 32 * 1024 * 1024);
+                                              size, MAX_PREALLOC_SIZE);
         return 0;
 }