[PATCH 1/1] UBUNTU: SAUCE: Increase the default prealloc buffer for HDA audio devices (non-modem)

[Brad Figg]

This allows for buffering of up to 4 seconds of audio. This is
intended to improve the audio experience. This patch is being
carried by Fedora but is not upstream.

Signed-off-by: Brad Figg <brad.figg at canonical.com>
---
 sound/pci/hda/hda_intel.c |   14 +++++++++++++-
 1 files changed, 13 insertions(+), 1 deletions(-)

diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
index 6517f58..3f02c70 100644
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -1944,6 +1944,7 @@ azx_attach_pcm_stream(struct hda_bus *bus, struct hda_codec *codec,
 	struct azx_pcm *apcm;
 	int pcm_dev = cpcm->device;
 	int s, err;
+	size_t prealloc_min = 64*1024;	/* 64KB */
 
 	if (pcm_dev >= AZX_MAX_PCMS) {
 		snd_printk(KERN_ERR SFX "Invalid PCM device number %d\n",
@@ -1977,10 +1978,21 @@ azx_attach_pcm_stream(struct hda_bus *bus, struct hda_codec *codec,
 		if (cpcm->stream[s].substreams)
 			snd_pcm_set_ops(pcm, s, &azx_pcm_ops);
 	}
+
 	/* buffer pre-allocation */
+
+	/* subtle, don't allocate a big buffer for modems...
+	 * also, don't just test 32BIT_MASK, since azx supports
+	 * 64-bit DMA in some cases.
+	 */
+	/* lennart wants a 2.2MB buffer for 2sec of 48khz */
+	if (pcm->dev_class == SNDRV_PCM_CLASS_GENERIC &&
+	    chip->pci->dma_mask >= DMA_32BIT_MASK)
+		prealloc_min = 4 * 1024 * 1024;	/* 4MB */
+
 	snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_DEV_SG,
 					      snd_dma_pci_data(chip->pci),
-					      1024 * 64, 32 * 1024 * 1024);
+					      prealloc_min, 32 * 1024 * 1024);
 	return 0;
 }
 
-- 
1.6.4.4