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-rw-r--r--target/linux/xburst/patches-3.8/0016-ASoC-JZ4740-Support-buffer-size-that-is-not-a-multip.patch89
1 files changed, 89 insertions, 0 deletions
diff --git a/target/linux/xburst/patches-3.8/0016-ASoC-JZ4740-Support-buffer-size-that-is-not-a-multip.patch b/target/linux/xburst/patches-3.8/0016-ASoC-JZ4740-Support-buffer-size-that-is-not-a-multip.patch
new file mode 100644
index 000000000..552f811d6
--- /dev/null
+++ b/target/linux/xburst/patches-3.8/0016-ASoC-JZ4740-Support-buffer-size-that-is-not-a-multip.patch
@@ -0,0 +1,89 @@
+From 8a5087fe59e31efb8641e704058328997c3c8ff1 Mon Sep 17 00:00:00 2001
+From: Maarten ter Huurne <maarten@treewalker.org>
+Date: Wed, 10 Aug 2011 00:25:11 +0200
+Subject: [PATCH 16/21] ASoC: JZ4740: Support buffer size that is not a
+ multiple of period size.
+
+This fixes glitches triggered by libao, which sets time-based intervals
+instead of byte-based intervals like SDL does.
+
+Thanks to Paul Cercueil for figuring out that the buffer size was causing
+the glitches and to Lars Clausen for helping me write the fix.
+---
+ sound/soc/jz4740/jz4740-pcm.c | 21 ++++++++++++++++++---
+ 1 files changed, 18 insertions(+), 3 deletions(-)
+
+--- a/sound/soc/jz4740/jz4740-pcm.c
++++ b/sound/soc/jz4740/jz4740-pcm.c
+@@ -31,6 +31,7 @@
+
+ struct jz4740_runtime_data {
+ unsigned long dma_period;
++ unsigned long dma_period_left;
+ dma_addr_t dma_start;
+ dma_addr_t dma_pos;
+ dma_addr_t dma_end;
+@@ -67,10 +68,13 @@ static void jz4740_pcm_start_transfer(st
+ if (prtd->dma_pos == prtd->dma_end)
+ prtd->dma_pos = prtd->dma_start;
+
+- if (prtd->dma_pos + prtd->dma_period > prtd->dma_end)
++ if (prtd->dma_period_left == 0)
++ prtd->dma_period_left = prtd->dma_period;
++
++ if (prtd->dma_pos + prtd->dma_period_left > prtd->dma_end)
+ count = prtd->dma_end - prtd->dma_pos;
+ else
+- count = prtd->dma_period;
++ count = prtd->dma_period_left;
+
+ jz4740_dma_disable(prtd->dma);
+
+@@ -85,6 +89,7 @@ static void jz4740_pcm_start_transfer(st
+ jz4740_dma_set_transfer_count(prtd->dma, count);
+
+ prtd->dma_pos += count;
++ prtd->dma_period_left -= count;
+
+ jz4740_dma_enable(prtd->dma);
+ }
+@@ -96,7 +101,8 @@ static void jz4740_pcm_dma_transfer_done
+ struct snd_pcm_runtime *runtime = substream->runtime;
+ struct jz4740_runtime_data *prtd = runtime->private_data;
+
+- snd_pcm_period_elapsed(substream);
++ if (prtd->dma_period_left == 0)
++ snd_pcm_period_elapsed(substream);
+
+ jz4740_pcm_start_transfer(prtd, substream);
+ }
+@@ -133,6 +139,7 @@ static int jz4740_pcm_hw_params(struct s
+ runtime->dma_bytes = params_buffer_bytes(params);
+
+ prtd->dma_period = params_period_bytes(params);
++ prtd->dma_period_left = 0;
+ prtd->dma_start = runtime->dma_addr;
+ prtd->dma_pos = prtd->dma_start;
+ prtd->dma_end = prtd->dma_start + runtime->dma_bytes;
+@@ -160,6 +167,7 @@ static int jz4740_pcm_prepare(struct snd
+ if (!prtd->dma)
+ return -EBUSY;
+
++ prtd->dma_period_left = 0;
+ prtd->dma_pos = prtd->dma_start;
+
+ return 0;
+@@ -219,6 +227,13 @@ static int jz4740_pcm_open(struct snd_pc
+ if (prtd == NULL)
+ return -ENOMEM;
+
++ /* Force period and buffer size to be a multiple of the DMA transfer
++ * size, which is 16 bytes. */
++ snd_pcm_hw_constraint_step(runtime, 0,
++ SNDRV_PCM_HW_PARAM_PERIOD_BYTES, 16);
++ snd_pcm_hw_constraint_step(runtime, 0,
++ SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 16);
++
+ snd_soc_set_runtime_hwparams(substream, &jz4740_pcm_hardware);
+
+ runtime->private_data = prtd;