From 345c03ef0f2bd0c933a1eca27732af7edf5e8d4d Mon Sep 17 00:00:00 2001 From: Clemens Ladisch Date: Mon, 25 May 2009 10:05:00 +0200 Subject: [PATCH] sound: oxygen: reset DMA when stream is closed 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 Signed-off-by: Takashi Iwai --- sound/pci/oxygen/oxygen_pcm.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/sound/pci/oxygen/oxygen_pcm.c b/sound/pci/oxygen/oxygen_pcm.c index c262049961e1..3b5ca70c9d4d 100644 --- a/sound/pci/oxygen/oxygen_pcm.c +++ b/sound/pci/oxygen/oxygen_pcm.c @@ -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); -- 2.39.5