[alsa-devel] [PATCH] ASoC: Fix DMA channel leak in imx-pcm-dma-mx2 driver.

[Javier Martin]

"snd_imx_pcm_hw_params" callback can be called
several times by the user (i.e. OSS emulation)
leading to a DMA channel leak.

Signed-off-by: Javier Martin <javier.martin at vista-silicon.com>
---
 sound/soc/imx/imx-pcm-dma-mx2.c |   12 +++++++-----
 1 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/sound/soc/imx/imx-pcm-dma-mx2.c b/sound/soc/imx/imx-pcm-dma-mx2.c
index 43fdc24..d2bb1cb 100644
--- a/sound/soc/imx/imx-pcm-dma-mx2.c
+++ b/sound/soc/imx/imx-pcm-dma-mx2.c
@@ -88,11 +88,13 @@ static int imx_ssi_dma_alloc(struct snd_pcm_substream *substream,
 	iprtd->dma_data.dma_request = dma_params->dma;
 
 	/* Try to grab a DMA channel */
-	dma_cap_zero(mask);
-	dma_cap_set(DMA_SLAVE, mask);
-	iprtd->dma_chan = dma_request_channel(mask, filter, iprtd);
-	if (!iprtd->dma_chan)
-		return -EINVAL;
+	if (!iprtd->dma_chan) {
+		dma_cap_zero(mask);
+		dma_cap_set(DMA_SLAVE, mask);
+		iprtd->dma_chan = dma_request_channel(mask, filter, iprtd);
+		if (!iprtd->dma_chan)
+			return -EINVAL;
+	}
 
 	switch (params_format(params)) {
 	case SNDRV_PCM_FORMAT_S16_LE:
-- 
1.7.0.4