[PATCH 3.16 100/370] ALSA: hiface: Fix M2Tech hiFace driver sampling rate change

[Ben Hutchings]

3.16.42-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Jussi Laako <jussi@xxxxxxxxxxxxx>

commit 995c6a7fd9b9212abdf01160f6ce3193176be503 upstream.

Sampling rate changes after first set one are not reflected to the
hardware, while driver and ALSA think the rate has been changed.

Fix the problem by properly stopping the interface at the beginning of
prepare call, allowing new rate to be set to the hardware. This keeps
the hardware in sync with the driver.

Signed-off-by: Jussi Laako <jussi@xxxxxxxxxxxxx>
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 sound/usb/hiface/pcm.c | 2 ++
 1 file changed, 2 insertions(+)

--- a/sound/usb/hiface/pcm.c
+++ b/sound/usb/hiface/pcm.c
@@ -445,6 +445,8 @@ static int hiface_pcm_prepare(struct snd
 
 	mutex_lock(&rt->stream_mutex);
 
+	hiface_pcm_stream_stop(rt);
+
 	sub->dma_off = 0;
 	sub->period_off = 0;