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soundwire: intel: don't save hw_params for use in prepare 

[ Upstream commit 0a0d1740bd ]

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: a5a0239c27 ("soundwire: intel: reinitialize IP+DSP in .prepare(), but only when resuming")
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Péter Ujfalusi <peter.ujfalusi@linux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20230321022642.1426611-1-yung-chuan.liao@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Pierre-Louis Bossart 2023-03-21 10:26:42 +08:00 committed by Greg Kroah-Hartman
parent 840dab1a4c
commit 7cfd350db9
2 changed files with 7 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/soundwire/cadence_master.h
View File

@ -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;

11
drivers/soundwire/intel.c
View File

@ -833,7 +833,6 @@ 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,
@ -886,6 +885,11 @@ 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;
/*
@ -897,7 +901,7 @@ 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
@ -909,7 +913,7 @@ 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);
}
@ -948,7 +952,6 @@ 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;