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sound: oxygen: reset DMA when stream is closed

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When a PCM stream is closed, flush the corresponding DMA channel.
Otherwise, the DMA controller would continue to output the last sample
which would result in a DC offset on the output.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Clemens Ladisch 2009-05-25 10:05:00 +02:00 committed by Takashi Iwai
parent 59a3759d0f
commit 345c03ef0f
1 changed files with 5 additions and 1 deletions
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6
sound/pci/oxygen/oxygen_pcm.c
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@ -487,10 +487,14 @@ static int oxygen_hw_free(struct snd_pcm_substream *substream)
{
struct oxygen *chip = snd_pcm_substream_chip(substream);
unsigned int channel = oxygen_substream_channel(substream);
unsigned int channel_mask = 1 << channel;
spin_lock_irq(&chip->reg_lock);
chip->interrupt_mask &= ~(1 << channel);
chip->interrupt_mask &= ~channel_mask;
oxygen_write16(chip, OXYGEN_INTERRUPT_MASK, chip->interrupt_mask);
oxygen_set_bits8(chip, OXYGEN_DMA_FLUSH, channel_mask);
oxygen_clear_bits8(chip, OXYGEN_DMA_FLUSH, channel_mask);
spin_unlock_irq(&chip->reg_lock);
return snd_pcm_lib_free_pages(substream);