[PATCH v2 2/3] ALSA: hda: Add dma stop delay variable

[Mohan Kumar]

A variable dma_stop_delay is added as a new member in hdac_bus
structure to avoid memory decode error incase DMA RUN bit is not
disabled in the given timeout from snd_hdac_stream_sync function and
followed by stream reset which results in memory decode error between
reset set and clear operation.

Signed-off-by: Mohan Kumar <mkumard at nvidia.com>
---
 include/sound/hdaudio.h | 3 +++
 sound/hda/hdac_stream.c | 7 +++++++
 2 files changed, 10 insertions(+)

diff --git a/include/sound/hdaudio.h b/include/sound/hdaudio.h
index c1f78d9a6e47..6eed61e6cf8a 100644
--- a/include/sound/hdaudio.h
+++ b/include/sound/hdaudio.h
@@ -347,6 +347,9 @@ struct hdac_bus {
 
 	int bdl_pos_adj;		/* BDL position adjustment */
 
+	/* delay time in us for dma stop */
+	unsigned int dma_stop_delay;
+
 	/* locks */
 	spinlock_t reg_lock;
 	struct mutex cmd_mutex;
diff --git a/sound/hda/hdac_stream.c b/sound/hda/hdac_stream.c
index a38a2af1654f..abe7a1b16fe1 100644
--- a/sound/hda/hdac_stream.c
+++ b/sound/hda/hdac_stream.c
@@ -150,9 +150,12 @@ void snd_hdac_stream_reset(struct hdac_stream *azx_dev)
 {
 	unsigned char val;
 	int timeout;
+	int dma_run_state;
 
 	snd_hdac_stream_clear(azx_dev);
 
+	dma_run_state = snd_hdac_stream_readb(azx_dev, SD_CTL) & SD_CTL_DMA_START;
+
 	snd_hdac_stream_updateb(azx_dev, SD_CTL, 0, SD_CTL_STREAM_RESET);
 	udelay(3);
 	timeout = 300;
@@ -162,6 +165,10 @@ void snd_hdac_stream_reset(struct hdac_stream *azx_dev)
 		if (val)
 			break;
 	} while (--timeout);
+
+	if (azx_dev->bus->dma_stop_delay && dma_run_state)
+		udelay(azx_dev->bus->dma_stop_delay);
+
 	val &= ~SD_CTL_STREAM_RESET;
 	snd_hdac_stream_writeb(azx_dev, SD_CTL, val);
 	udelay(3);
-- 
2.17.1