2024-01-29 07:19:14

by Chancel Liu

Subject: [PATCH] ASoC: soc-core.c: Prefer to return dai->driver->name in snd_soc_dai_name_get()

ASoC machine driver can use snd_soc_{of_}get_dlc() (A) to get DAI name
for dlc (snd_soc_dai_link_component). In this function call
dlc->dai_name is parsed via snd_soc_dai_name_get() (B).

(A) int snd_soc_get_dlc(...)
{
...
(B) dlc->dai_name = snd_soc_dai_name_get(dai);
...
}

(B) has a priority to return dai->name as dlc->dai_name. In most cases
card can probe successfully. However it has an issue that ASoC tries to
rebind card. Here is a simplified flow for example:

| a) Card probes successfully at first
| b) One of the component bound to this card is removed for some
| reason the component->dev is released
| c) That component is re-registered
v d) ASoC calls snd_soc_try_rebind_card()

a) points dlc->dai_name to dai->name. b) releases all resource of the
old DAI. c) creates new DAI structure. In result d) can not use
dlc->dai_name to add new created DAI.

So it's reasonable that prefer to return dai->driver->name in
snd_soc_dai_name_get() because dai->driver is a pre-defined global
variable.

Signed-off-by: Chancel Liu <[email protected]>
---
sound/soc/soc-core.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index 516350533e73..09467c693627 100644
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -300,12 +300,12 @@ static int snd_soc_is_matching_dai(const struct snd_soc_dai_link_component *dlc,
const char *snd_soc_dai_name_get(struct snd_soc_dai *dai)
{
/* see snd_soc_is_matching_dai() */
- if (dai->name)
- return dai->name;
-
if (dai->driver->name)
return dai->driver->name;

+ if (dai->name)
+ return dai->name;
+
if (dai->component->name)
return dai->component->name;

--
2.43.0

2024-01-29 23:46:33

by Kuninori Morimoto

Subject: Re: [PATCH] ASoC: soc-core.c: Prefer to return dai->driver->name in snd_soc_dai_name_get()

Hi Chancel

Thank you for the patch

> diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
> index 516350533e73..09467c693627 100644
> --- a/sound/soc/soc-core.c
> +++ b/sound/soc/soc-core.c
> @@ -300,12 +300,12 @@ static int snd_soc_is_matching_dai(const struct snd_soc_dai_link_component *dlc,
> const char *snd_soc_dai_name_get(struct snd_soc_dai *dai)
> {
> /* see snd_soc_is_matching_dai() */
> - if (dai->name)
> - return dai->name;
> -
> if (dai->driver->name)
> return dai->driver->name;
>
> + if (dai->name)
> + return dai->name;
> +
> if (dai->component->name)
> return dai->component->name;
>
> --

As above comment indicated, snd_soc_dai_name_get() and
snd_soc_is_matching_dai() are paired.
If you want to update snd_soc_dai_name_get(), updating
snd_soc_is_matching_dai() also is good idea.


Thank you for your help !!

Best regards
---
Renesas Electronics
Ph.D. Kuninori Morimoto