Re: [PATCH 1/2] ALSA: hda: cs35l56: Put ACPI device after setting companion

[Richard Fitzgerald <rf@opensource.cirrus.com>]

On 28/04/2026 9:01 am, Shuhao Fu wrote:
> acpi_dev_get_first_match_dev() returns a refcounted ACPI device and
> callers are expected to balance it with acpi_dev_put().
> 
> When no companion is already attached, cs35l56_hda_read_acpi() looks
> up an ACPI device and sets it with ACPI_COMPANION_SET(), but leaves
> the lookup reference held.
> 
> ACPI_COMPANION_SET() does not take ownership of that reference, so
> drop it with acpi_dev_put() after attaching the companion.

Are you sure about this?
I remember when I wrote this code I checked the driver core and saw that
if there is a companion it puts it when the driver is removed.
That is why I didn't put the reference here, it would have caused a
double put.

> 
> Fixes: 73cfbfa9caea ("ALSA: hda/cs35l56: Add driver for Cirrus Logic CS35L56 amplifier")
> Signed-off-by: Shuhao Fu <sfual@cse.ust.hk>
> ---
>   sound/hda/codecs/side-codecs/cs35l56_hda.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/sound/hda/codecs/side-codecs/cs35l56_hda.c b/sound/hda/codecs/side-codecs/cs35l56_hda.c
> index 1ace4beef50857b..16a5a40899b2873 100644
> --- a/sound/hda/codecs/side-codecs/cs35l56_hda.c
> +++ b/sound/hda/codecs/side-codecs/cs35l56_hda.c
> @@ -1032,6 +1032,7 @@ static int cs35l56_hda_read_acpi(struct cs35l56_hda *cs35l56, int hid, int id)
>   			return -ENODEV;
>   		}
>   		ACPI_COMPANION_SET(cs35l56->base.dev, adev);
> +		acpi_dev_put(adev);
>   	}
>   
>   	/* Initialize things that could be overwritten by a fixup */