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authorPierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>2022-06-22 01:56:40 +0300
committerVinod Koul <vkoul@kernel.org>2022-07-06 10:04:21 +0300
commit3e9c9f90573f4633ec8270d0d02bcea4fad1e802 (patch)
tree222ce296694da6db32d2bbeae77d48a97b8cd8a0 /drivers/soundwire
parent9a24bb35b0d81edb826f174d7752c2a54bc00abd (diff)
downloadlinux-3e9c9f90573f4633ec8270d0d02bcea4fad1e802.tar.xz
soundwire: intel: use pm_runtime_resume() on component probe
During the card registration, transactions on the SoundWire bus can be initiated. If the ALSA card is registered after the bus suspends, timeouts can be seen while reading/writing codec registers. This is extremely easy to reproduce in driver bind/unbind tests. In an initial experiment, the ASoC soc-component.c code was modified to initiate a pm_runtime resume on a component probe. The results showed this was too invasive. Instead this patch suggests resuming the SoundWire component only. Because of the parent-child hierarchy enforced by the pm_runtime framework, it can be argued that the codec component probe should be enough to resume all necessary devices, and indeed the same resume will be applied to SoundWire codecs used on Intel platforms. Calling pm_runtime_resume() on both the Intel and codec sides has the benefit of resuming the bus without assuming any order during the card registration. The first component on a dailink to be probed will resume the bus. In addition, if a codec driver did not implement this transition, the Intel component would still resume the bus and avoid timeouts on card registration. BugLink: https://github.com/thesofproject/linux/issues/3651 Reviewed-by: Rander Wang <rander.wang@intel.com> Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com> Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com> Reviewed-by: Péter Ujfalusi <peter.ujfalusi@linux.intel.com> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> Link: https://lore.kernel.org/r/20220621225641.221170-4-pierre-louis.bossart@linux.intel.com Signed-off-by: Vinod Koul <vkoul@kernel.org>
Diffstat (limited to 'drivers/soundwire')
-rw-r--r--drivers/soundwire/intel.c18
1 files changed, 18 insertions, 0 deletions
diff --git a/drivers/soundwire/intel.c b/drivers/soundwire/intel.c
index 505c5ef061e3..95ce292994cc 100644
--- a/drivers/soundwire/intel.c
+++ b/drivers/soundwire/intel.c
@@ -1043,6 +1043,23 @@ static int intel_trigger(struct snd_pcm_substream *substream, int cmd, struct sn
return ret;
}
+static int intel_component_probe(struct snd_soc_component *component)
+{
+ int ret;
+
+ /*
+ * make sure the device is pm_runtime_active before initiating
+ * bus transactions during the card registration.
+ * We use pm_runtime_resume() here, without taking a reference
+ * and releasing it immediately.
+ */
+ ret = pm_runtime_resume(component->dev);
+ if (ret < 0 && ret != -EACCES)
+ return ret;
+
+ return 0;
+}
+
static int intel_component_dais_suspend(struct snd_soc_component *component)
{
struct snd_soc_dai *dai;
@@ -1098,6 +1115,7 @@ static const struct snd_soc_dai_ops intel_pcm_dai_ops = {
static const struct snd_soc_component_driver dai_component = {
.name = "soundwire",
+ .probe = intel_component_probe,
.suspend = intel_component_dais_suspend
};