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ASoC: dwc: fix dma stop transferring issue 

Designware I2S uses tx empty and rx available signals as the DMA
handshaking signals. during music playing, if XRUN occurs,
i2s_stop() function will be executed and both tx and rx irq are
masked, when music continues to be played, i2s_start() is executed
but both tx and rx irq are not unmasked which cause I2S stop
sending DMA handshaking signal to DMA controller, and it finally
causes music playing will be stopped once XRUN occurs for the first
time.

[On list discussion suggests this may be partly a race condition on slow
systems -- broonie]

Signed-off-by: Yitian Bu <yitian.bu@tangramtek.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
yitian 2015-09-29 22:43:17 +08:00 committed by Mark Brown
parent 4873867e5f
commit 924eb47512
1 changed files with 12 additions and 3 deletions
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15
sound/soc/dwc/designware_i2s.c
View File

@ -141,13 +141,22 @@ static inline void i2s_clear_irqs(struct dw_i2s_dev *dev, u32 stream)
static void i2s_start(struct dw_i2s_dev *dev,
struct snd_pcm_substream *substream)
{
u32 i, irq;
i2s_write_reg(dev->i2s_base, IER, 1);
if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
for (i = 0; i < 4; i++) {
irq = i2s_read_reg(dev->i2s_base, IMR(i));
i2s_write_reg(dev->i2s_base, IMR(i), irq & ~0x30);
}
i2s_write_reg(dev->i2s_base, ITER, 1);
else
} else {
for (i = 0; i < 4; i++) {
irq = i2s_read_reg(dev->i2s_base, IMR(i));
i2s_write_reg(dev->i2s_base, IMR(i), irq & ~0x03);
}
i2s_write_reg(dev->i2s_base, IRER, 1);
}
i2s_write_reg(dev->i2s_base, CER, 1);
}