There have been a couple of customer reports of intermittant issues after system resume, where sometimes the DSP firmware stops responding. Investigations into this issue show that there is a race between receiving a prepare from the HDA core, and the firmware reload which is started by the system resume. This can causes the Global Enable on the CS35L41 to be enabled during the firmware load, which can sometimes cause issues in the DSP.
The existing system resume behaviour also did not resume the audio, if audio was previously playing when it was suspended. In addition, during investigation, it was found there were additional problems in the System Resume sequence, as well as the Playback sequence with External Boost, where the driver does not correctly follow its enable sequence for this mode. This can cause additional issues such as pops and clicks.
This chain intends to correct the sequences for playback and system suspend/resume so that the driver: obeys the external boost enable sequence; resumes audio on system resume; and avoids the race condition on firmware load and playback during system resume.
Stefan Binding (11): ALSA: cs35l41: Use mbox command to enable speaker output for external boost ALSA: hda: cs35l41: Check mailbox status of pause command after firmware load ALSA: hda: cs35l41: Ensure we correctly re-sync regmap before system suspending. ALSA: hda: cs35l41: Ensure we pass up any errors during system suspend. ALSA: hda: cs35l41: Move Play and Pause into separate functions ALSA: hda: hda_component: Add pre and post playback hooks to hda_component ALSA: hda: cs35l41: Use pre and post playback hooks ALSA: hda: cs35l41: Rework System Suspend to ensure correct call separation ALSA: hda/realtek: Support pre-/post- playback hooks for cs35l41 ALSA: hda: cs35l41: Add device_link between HDA and cs35l41_hda ALSA: hda: cs35l41: Ensure amp is only unmuted during playback
include/sound/cs35l41.h | 5 +- sound/pci/hda/cs35l41_hda.c | 288 +++++++++++++++++++++++++-------- sound/pci/hda/hda_component.h | 2 + sound/pci/hda/patch_realtek.c | 10 +- sound/soc/codecs/cs35l41-lib.c | 118 ++++++++++++-- sound/soc/codecs/cs35l41.c | 18 +-- 6 files changed, 343 insertions(+), 98 deletions(-)