[PATCH] ASoC: hdac_hda: Keep runtime PM state in sync across codec remove/probe

[Peter Ujfalusi <peter.ujfalusi@linux.intel.com>]

After the codec has been removed, its runtime PM status is
RPM_SUSPENDED while hdac_hda_codec_probe() powers the codec up via
snd_hda_codec_device_new(). The pm_runtime_put()/snd_hda_power_down()
calls on probe and registration then see an already suspended device,
the codec suspend callback is not called and the codec, its HDA link and
the codec_powered bit stay set, preventing the controller from runtime
suspending.

The remove has a similar problem with the codec link accounting:
hdac_hda_codec_remove() drops the link reference taken in probe without
looking at the runtime PM state of the codec. If the codec was already
runtime suspended, the link reference has been dropped by the codec
suspend callback and the remove drops it a second time.

Resume the codec in hdac_hda_codec_remove() before disabling runtime PM
so that the link reference and the codec_powered bit are always in the
same state as after the probe, and mark the device active on probe once
the codec has been powered up.

Finally mark the codec device suspended at the end of the remove. Its
runtime PM is disabled at this point and if only the ASoC card is
unbound (e.g. by unbinding the machine driver), a following system
suspend would otherwise call the runtime suspend callback on the already
cleaned up codec via pm_runtime_force_suspend().

This is a followup patch to address Sashiko reports.

Link: https://lore.kernel.org/linux-sound/20261027083840.28813-4-peter.ujfalusi@linux.intel.com/
Fixes: c3ec8ac82105 ("ASoC: hdac_hda: fix memleak on module unload")
Cc: stable@vger.kernel.org
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
---
Hi,

this is an incremental update for
https://lore.kernel.org/linux-sound/20261027083840.28813-4-peter.ujfalusi@linux.intel.com/

to address Sashiko concerns and validated again on hardware.

I think this is the first time the unbind/bind was used for the HDA codec
with SOF stack, so the real world impact is low, but never the less, it has
been broken eversince hdac_hda is used.

Regards,
Peter 

 sound/soc/codecs/hdac_hda.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/sound/soc/codecs/hdac_hda.c b/sound/soc/codecs/hdac_hda.c
index bd4b113401a8..48eb95973b7a 100644
--- a/sound/soc/codecs/hdac_hda.c
+++ b/sound/soc/codecs/hdac_hda.c
@@ -514,6 +514,9 @@ static int hdac_hda_codec_probe(struct snd_soc_component *component)
 		snd_hdac_display_power(hdev->bus,
 				       HDA_CODEC_IDX_CONTROLLER, false);
 
+	/* The codec is in D0, the status is RPM_SUSPENDED after a previous unbind */
+	pm_runtime_set_active(&hdev->dev);
+
 	/* match for forbid call in snd_hda_codec_device_new() */
 	pm_runtime_allow(&hdev->dev);
 
@@ -554,6 +557,12 @@ static void hdac_hda_codec_remove(struct snd_soc_component *component)
 		return;
 	}
 
+	/*
+	 * Resume the codec to have its link reference (dropped below) and
+	 * codec_powered bit in the same state as after the probe.
+	 */
+	pm_runtime_get_sync(&hdev->dev);
+
 	/* prevent runtime PM callbacks while the link and the codec are torn down */
 	pm_runtime_disable(&hdev->dev);
 	snd_hdac_ext_bus_link_put(hdev->bus, hlink);
@@ -565,6 +574,9 @@ static void hdac_hda_codec_remove(struct snd_soc_component *component)
 
 	/* Balances the disable above, cleanup_for_unbind keeps runtime PM disabled */
 	pm_runtime_enable(&hdev->dev);
+	pm_runtime_put_noidle(&hdev->dev);
+	/* The codec is cleaned up, system suspend must skip it from now on */
+	pm_runtime_set_suspended(&hdev->dev);
 }
 
 static const struct snd_soc_dapm_route hdac_hda_dapm_routes[] = {
-- 
2.56.0