From c7a8f049b828dc8e01acd56911a1816b7725d9c3 Mon Sep 17 00:00:00 2001
From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Date: Tue, 14 Jan 2020 17:52:25 -0600
Subject: [PATCH] soundwire: stream: do not update parameters during DISABLED-PREPARED transition
Git-commit: c7a8f049b828dc8e01acd56911a1816b7725d9c3
Patch-mainline: v5.7-rc1
References: jsc#SLE-16518

After a system suspend, the ALSA/ASoC core will invoke the .prepare()
callback and a TRIGGER_START when INFO_RESUME is not supported.

Likewise, when an underflow occurs, the .prepare callback will be invoked.

In both cases, the stream can be in DISABLED mode, and will transition
into the PREPARED mode. We however don't want the bus bandwidth to be
recomputed.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20200114235227.14502-4-pierre-louis.bossart@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/soundwire/stream.c | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/drivers/soundwire/stream.c b/drivers/soundwire/stream.c
index bd0bddf73830..c28ce7f0d742 100644
--- a/drivers/soundwire/stream.c
+++ b/drivers/soundwire/stream.c
@@ -1460,7 +1460,8 @@ static void sdw_release_bus_lock(struct sdw_stream_runtime *stream)
 	}
 }
 
-static int _sdw_prepare_stream(struct sdw_stream_runtime *stream)
+static int _sdw_prepare_stream(struct sdw_stream_runtime *stream,
+			       bool update_params)
 {
 	struct sdw_master_runtime *m_rt;
 	struct sdw_bus *bus = NULL;
@@ -1480,6 +1481,9 @@ static int _sdw_prepare_stream(struct sdw_stream_runtime *stream)
 			return -EINVAL;
 		}
 
+		if (!update_params)
+			goto program_params;
+
 		/* Increment cumulative bus bandwidth */
 		/* TODO: Update this during Device-Device support */
 		bus->params.bandwidth += m_rt->stream->params.rate *
@@ -1495,6 +1499,7 @@ static int _sdw_prepare_stream(struct sdw_stream_runtime *stream)
 			}
 		}
 
+program_params:
 		/* Program params */
 		ret = sdw_program_params(bus);
 		if (ret < 0) {
@@ -1544,6 +1549,7 @@ static int _sdw_prepare_stream(struct sdw_stream_runtime *stream)
  */
 int sdw_prepare_stream(struct sdw_stream_runtime *stream)
 {
+	bool update_params = true;
 	int ret;
 
 	if (!stream) {
@@ -1567,7 +1573,16 @@ int sdw_prepare_stream(struct sdw_stream_runtime *stream)
 		goto state_err;
 	}
 
-	ret = _sdw_prepare_stream(stream);
+	/*
+	 * when the stream is DISABLED, this means sdw_prepare_stream()
+	 * is called as a result of an underflow or a resume operation.
+	 * In this case, the bus parameters shall not be recomputed, but
+	 * still need to be re-applied
+	 */
+	if (stream->state == SDW_STREAM_DISABLED)
+		update_params = false;
+
+	ret = _sdw_prepare_stream(stream, update_params);
 
 state_err:
 	sdw_release_bus_lock(stream);
-- 
2.16.4