linux-kernel - Re: [PATCH AUTOSEL 5.2 072/185] ALSA: hda: Add codec on bus address table lately

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Message-ID: <s5h8sqgm9qz.wl-tiwai@suse.de>
Date:   Sun, 22 Sep 2019 21:06:12 +0200
From:   Takashi Iwai <tiwai@...e.de>
To:     Sasha Levin <sashal@...nel.org>
Cc:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH AUTOSEL 5.2 072/185] ALSA: hda: Add codec on bus address table lately

On Sun, 22 Sep 2019 20:47:30 +0200,
Sasha Levin wrote:
> 
> From: Takashi Iwai <tiwai@...e.de>
> 
> [ Upstream commit ee5f85d9290fe25d460bd320b7fe073075d72d33 ]
> 
> The call of snd_hdac_bus_add_device() is needed only for registering
> the codec onto the bus caddr_tbl[] that is referred essentially only
> in the unsol event handler.  That is, the reason of this call and the
> release by the counter-part function snd_hdac_bus_remove_device() is
> just to assure that the unsol event gets notified to the codec.
> 
> But the current implementation of the unsol notification wouldn't work
> properly when the codec is still in a premature init state.  So this
> patch tries to work around it by delaying the caddr_tbl[] registration
> at the point of snd_hdac_device_register().
> 
> Also, the order of snd_hdac_bus_remove_device() and device_del() calls
> are shuffled to make sure that the unsol event is masked before
> deleting the device.
> 
> BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=204565
> Signed-off-by: Takashi Iwai <tiwai@...e.de>
> Signed-off-by: Sasha Levin <sashal@...nel.org>

The upstream commit was reverted later by 246bb4aaa4f4, which has even
Fixes tag pointing this.  So please drop this.

BTW, this is the second time AUTOSEL overlooked the existing revert.
I'm afraid something is missing in the check.


thanks,

Takashi

> ---
>  sound/hda/hdac_device.c | 21 ++++++++++++---------
>  1 file changed, 12 insertions(+), 9 deletions(-)
> 
> diff --git a/sound/hda/hdac_device.c b/sound/hda/hdac_device.c
> index 3842f9d34b7cf..02b2950d1d0e6 100644
> --- a/sound/hda/hdac_device.c
> +++ b/sound/hda/hdac_device.c
> @@ -61,10 +61,6 @@ int snd_hdac_device_init(struct hdac_device *codec, struct hdac_bus *bus,
>  	pm_runtime_get_noresume(&codec->dev);
>  	atomic_set(&codec->in_pm, 0);
>  
> -	err = snd_hdac_bus_add_device(bus, codec);
> -	if (err < 0)
> -		goto error;
> -
>  	/* fill parameters */
>  	codec->vendor_id = snd_hdac_read_parm(codec, AC_NODE_ROOT,
>  					      AC_PAR_VENDOR_ID);
> @@ -143,15 +139,22 @@ int snd_hdac_device_register(struct hdac_device *codec)
>  	err = device_add(&codec->dev);
>  	if (err < 0)
>  		return err;
> +	err = snd_hdac_bus_add_device(codec->bus, codec);
> +	if (err < 0)
> +		goto error;
>  	mutex_lock(&codec->widget_lock);
>  	err = hda_widget_sysfs_init(codec);
>  	mutex_unlock(&codec->widget_lock);
> -	if (err < 0) {
> -		device_del(&codec->dev);
> -		return err;
> -	}
> +	if (err < 0)
> +		goto error_remove;
>  
>  	return 0;
> +
> + error_remove:
> +	snd_hdac_bus_remove_device(codec->bus, codec);
> + error:
> +	device_del(&codec->dev);
> +	return err;
>  }
>  EXPORT_SYMBOL_GPL(snd_hdac_device_register);
>  
> @@ -165,8 +168,8 @@ void snd_hdac_device_unregister(struct hdac_device *codec)
>  		mutex_lock(&codec->widget_lock);
>  		hda_widget_sysfs_exit(codec);
>  		mutex_unlock(&codec->widget_lock);
> -		device_del(&codec->dev);
>  		snd_hdac_bus_remove_device(codec->bus, codec);
> +		device_del(&codec->dev);
>  	}
>  }
>  EXPORT_SYMBOL_GPL(snd_hdac_device_unregister);
> -- 
> 2.20.1
>