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Commit 3e9c9f90 authored by Pierre-Louis Bossart's avatar Pierre-Louis Bossart Committed by Vinod Koul
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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: default avatarRander Wang <rander.wang@intel.com>
Reviewed-by: default avatarRanjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: default avatarBard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: default avatarPéter Ujfalusi <peter.ujfalusi@linux.intel.com>
Signed-off-by: default avatarPierre-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: default avatarVinod Koul <vkoul@kernel.org>
parent 9a24bb35
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