From: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
The existing code copies the hw_params pointer and reuses it later in
.prepare, specifically to re-initialize the ALH DMA channel
information that's lost in suspend-resume cycles.
This is not needed, we can directly access the information from the
substream/rtd - as done for the HDAudio DAIs in
sound/soc/sof/intel/hda-dai.c
In addition, using the saved pointer causes the suspend-resume test
cases to fail on specific platforms, depending on which version of GCC
is used. Péter Ujfalusi and I have spent long hours to root-cause this
problem that was reported by the Intel CI first with 6.2-rc1 and again
v6.3-rc1. In the latter case we were lucky that the problem was 100%
reproducible on local test devices, and found out that adding a
dev_dbg() or adding a call to usleep_range() just before accessing the
saved pointer "fixed" the issue. With errors appearing just by
changing the compiler version or minor changes in the code generated,
clearly we have a memory management Heisenbug.
The root-cause seems to be that the hw_params pointer is not
persistent. The soc-pcm code allocates the hw_params structure on the
stack, and passes it to the BE dailink hw_params and DAIs
hw_params. Saving such a pointer and reusing it later during the
.prepare stage cannot possibly work reliably, it's broken-by-design
since v5.10. It's astonishing that the problem was not seen earlier.
This simple fix will have to be back-ported to -stable, due to changes
to avoid the use of the get/set_dmadata routines this patch will only
apply on kernels older than v6.1.
Fixes: a5a0239c27fe ("soundwire: intel: reinitialize IP+DSP in .prepare(), but only when resuming")
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@xxxxxxxxxxxxxxx>
Reviewed-by: Péter Ujfalusi <peter.ujfalusi@xxxxxxxxxxxxxxx>
Signed-off-by: Bard Liao <yung-chuan.liao@xxxxxxxxxxxxxxx>
---
drivers/soundwire/cadence_master.h | 2 --
drivers/soundwire/intel.c | 11 +++++++----
2 files changed, 7 insertions(+), 6 deletions(-)
diff --git a/drivers/soundwire/cadence_master.h b/drivers/soundwire/cadence_master.h
index b653734085d9..27c56274217f 100644
--- a/drivers/soundwire/cadence_master.h
+++ b/drivers/soundwire/cadence_master.h
@@ -84,7 +84,6 @@ struct sdw_cdns_stream_config {
* @bus: Bus handle
* @stream_type: Stream type
* @link_id: Master link id
- * @hw_params: hw_params to be applied in .prepare step
* @suspended: status set when suspended, to be used in .prepare
* @paused: status set in .trigger, to be used in suspend
* @direction: stream direction
@@ -96,7 +95,6 @@ struct sdw_cdns_dai_runtime {
struct sdw_bus *bus;
enum sdw_stream_type stream_type;
int link_id;
- struct snd_pcm_hw_params *hw_params;
bool suspended;
bool paused;
int direction;
diff --git a/drivers/soundwire/intel.c b/drivers/soundwire/intel.c
index 046c67a2a39b..238acf5c97a9 100644
--- a/drivers/soundwire/intel.c
+++ b/drivers/soundwire/intel.c
@@ -725,7 +725,6 @@ static int intel_hw_params(struct snd_pcm_substream *substream,
dai_runtime->paused = false;
dai_runtime->suspended = false;
dai_runtime->pdi = pdi;
- dai_runtime->hw_params = params;
/* Inform DSP about PDI stream number */
ret = intel_params_stream(sdw, substream->stream, dai, params,
@@ -778,6 +777,11 @@ static int intel_prepare(struct snd_pcm_substream *substream,
}
if (dai_runtime->suspended) {
+ struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
+ struct snd_pcm_hw_params *hw_params;
+
+ hw_params = &rtd->dpcm[substream->stream].hw_params;
+
dai_runtime->suspended = false;
/*
@@ -789,7 +793,7 @@ static int intel_prepare(struct snd_pcm_substream *substream,
*/
/* configure stream */
- ch = params_channels(dai_runtime->hw_params);
+ ch = params_channels(hw_params);
if (substream->stream == SNDRV_PCM_STREAM_CAPTURE)
dir = SDW_DATA_DIR_RX;
else
@@ -801,7 +805,7 @@ static int intel_prepare(struct snd_pcm_substream *substream,
/* Inform DSP about PDI stream number */
ret = intel_params_stream(sdw, substream->stream, dai,
- dai_runtime->hw_params,
+ hw_params,
sdw->instance,
dai_runtime->pdi->intel_alh_id);
}
@@ -840,7 +844,6 @@ intel_hw_free(struct snd_pcm_substream *substream, struct snd_soc_dai *dai)
return ret;
}
- dai_runtime->hw_params = NULL;
dai_runtime->pdi = NULL;
return 0;
--
2.25.1
