[alsa-devel] [PATCH] ASoC: audio-graph: indicate rebind issue

[alsa-devel] [PATCH] ASoC: audio-graph: indicate rebind issue

[Kuninori Morimoto]

From: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>

ALSA SoC try to rebind Sound Card if Card/CPU/Codec/Platform
were unbinded and re-binded again.
But, Audio Graph Card might can't rebind again if user do for example

	unbind CPU or Codec driver
	bind   CPU or Codec driver

Because Audio Graph Card is still pointing old/unbinded
CPU or Codec driver's DAI name at dlc->dai_name.

To avoid this issue, it needs to alloc memory and keep DAI name
even though if CPU or Codec driver was unbinded.
Or, always do unbind/bind at Sound Card.

For now, this patch indicates this issue as FIXME.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
---
 sound/soc/generic/audio-graph-card.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/sound/soc/generic/audio-graph-card.c b/sound/soc/generic/audio-graph-card.c
index 288df24..6007e63 100644
--- a/sound/soc/generic/audio-graph-card.c
+++ b/sound/soc/generic/audio-graph-card.c
@@ -129,6 +129,25 @@ static int asoc_simple_parse_dai(struct device_node *ep,
 	args.args[0]	= graph_get_dai_id(ep);
 	args.args_count	= (of_graph_get_endpoint_count(node) > 1);
 
+	/*
+	 * FIXME
+	 *
+	 * Here, dlc->dai_name is pointer to CPU/Codec DAI name.
+	 * If user unbinded CPU or Codec driver, but not for Sound Card,
+	 * dlc->dai_name is keeping unbinded CPU or Codec
+	 * driver's pointer.
+	 *
+	 * If user re-bind CPU or Codec driver again, ALSA SoC will try
+	 * to rebind Card via snd_soc_try_rebind_card(), but because of
+	 * above reason, it might can't bind Sound Card.
+	 * Because Sound Card is pointing to released dai_name pointer.
+	 *
+	 * To avoid this rebind Card issue,
+	 * 1) It needs to alloc memory to keep dai_name eventhough
+	 *    CPU or Codec driver was unbinded, or
+	 * 2) user need to rebind Sound Card everytime
+	 *    if he unbinded CPU or Codec.
+	 */
 	ret = snd_soc_get_dai_name(&args, &dlc->dai_name);
 	if (ret < 0)
 		return ret;
-- 
2.7.4

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[alsa-devel] Applied "ASoC: audio-graph: indicate rebind issue" to the asoc tree

[Mark Brown]

The patch

   ASoC: audio-graph: indicate rebind issue

has been applied to the asoc tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-5.4

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

From 157ab71286e6dd71676052275ab5dfa3955c5cdb Mon Sep 17 00:00:00 2001
From: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Date: Tue, 3 Sep 2019 17:16:05 +0900
Subject: [PATCH] ASoC: audio-graph: indicate rebind issue

ALSA SoC try to rebind Sound Card if Card/CPU/Codec/Platform
were unbinded and re-binded again.
But, Audio Graph Card might can't rebind again if user do for example

	unbind CPU or Codec driver
	bind   CPU or Codec driver

Because Audio Graph Card is still pointing old/unbinded
CPU or Codec driver's DAI name at dlc->dai_name.

To avoid this issue, it needs to alloc memory and keep DAI name
even though if CPU or Codec driver was unbinded.
Or, always do unbind/bind at Sound Card.

For now, this patch indicates this issue as FIXME.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87sgpdu75m.wl-kuninori.morimoto.gx@renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>
---
 sound/soc/generic/audio-graph-card.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/sound/soc/generic/audio-graph-card.c b/sound/soc/generic/audio-graph-card.c
index 288df245b2f0..6007e6305735 100644
--- a/sound/soc/generic/audio-graph-card.c
+++ b/sound/soc/generic/audio-graph-card.c
@@ -129,6 +129,25 @@ static int asoc_simple_parse_dai(struct device_node *ep,
 	args.args[0]	= graph_get_dai_id(ep);
 	args.args_count	= (of_graph_get_endpoint_count(node) > 1);
 
+	/*
+	 * FIXME
+	 *
+	 * Here, dlc->dai_name is pointer to CPU/Codec DAI name.
+	 * If user unbinded CPU or Codec driver, but not for Sound Card,
+	 * dlc->dai_name is keeping unbinded CPU or Codec
+	 * driver's pointer.
+	 *
+	 * If user re-bind CPU or Codec driver again, ALSA SoC will try
+	 * to rebind Card via snd_soc_try_rebind_card(), but because of
+	 * above reason, it might can't bind Sound Card.
+	 * Because Sound Card is pointing to released dai_name pointer.
+	 *
+	 * To avoid this rebind Card issue,
+	 * 1) It needs to alloc memory to keep dai_name eventhough
+	 *    CPU or Codec driver was unbinded, or
+	 * 2) user need to rebind Sound Card everytime
+	 *    if he unbinded CPU or Codec.
+	 */
 	ret = snd_soc_get_dai_name(&args, &dlc->dai_name);
 	if (ret < 0)
 		return ret;
-- 
2.20.1

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