[PATCH 3/6] soundwire: stream: only prepare stream when it is configured.

From: Pierre-Louis Bossart
Date: Wed Jan 08 2020 - 12:55:06 EST


From: Bard Liao <yung-chuan.liao@xxxxxxxxxxxxxxx>

We don't need to prepare the stream again if the stream is already
prepared.

sdw_prepare_stream() could be called multiple times without calling
sdw_deprepare_stream(). We call sdw_prepare_stream() in the prepare
dai ops and sdw_deprepare_stream() in the hw_free dai ops. If an xrun
happens, sdw_prepare_stream() will be called but
sdw_deprepare_stream() will not, which results in an imbalance and an
invalid total bandwidth.

Signed-off-by: Bard Liao <yung-chuan.liao@xxxxxxxxxxxxxxx>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
---
drivers/soundwire/stream.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/soundwire/stream.c b/drivers/soundwire/stream.c
index 6aa0b5d370c0..bd0bddf73830 100644
--- a/drivers/soundwire/stream.c
+++ b/drivers/soundwire/stream.c
@@ -1544,7 +1544,7 @@ static int _sdw_prepare_stream(struct sdw_stream_runtime *stream)
*/
int sdw_prepare_stream(struct sdw_stream_runtime *stream)
{
- int ret = 0;
+ int ret;

if (!stream) {
pr_err("SoundWire: Handle not found for stream\n");
@@ -1553,6 +1553,11 @@ int sdw_prepare_stream(struct sdw_stream_runtime *stream)

sdw_acquire_bus_lock(stream);

+ if (stream->state == SDW_STREAM_PREPARED) {
+ ret = 0;
+ goto state_err;
+ }
+
if (stream->state != SDW_STREAM_CONFIGURED &&
stream->state != SDW_STREAM_DEPREPARED &&
stream->state != SDW_STREAM_DISABLED) {
--
2.20.1