linux-kernel - Re: [alsa-devel] [PATCH v2 09/11] ASoC: Intel: hdac

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Date:   Mon, 17 Jun 2019 23:36:46 +0200
From:   Takashi Iwai <tiwai@...e.de>
To:     "Ranjani Sridharan" <ranjani.sridharan@...ux.intel.com>
Cc:     <alsa-devel@...a-project.org>,
        "Amadeusz Sławiński" 
        <amadeuszx.slawinski@...ux.intel.com>,
        "Liam Girdwood" <lgirdwood@...il.com>,
        "Cezary Rojewski" <cezary.rojewski@...el.com>,
        "Mark Brown" <broonie@...nel.org>,
        "Pierre-Louis Bossart" <pierre-louis.bossart@...ux.intel.com>,
        "Jie Yang" <yang.jie@...ux.intel.com>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [alsa-devel] [PATCH v2 09/11] ASoC: Intel: hdac_hdmi: Set ops to NULL on remove

On Mon, 17 Jun 2019 22:51:42 +0200,
Ranjani Sridharan wrote:
> 
> On Mon, 2019-06-17 at 13:36 +0200, Amadeusz Sławiński wrote:
> > When we unload Skylake driver we may end up calling
> > hdac_component_master_unbind(), it uses acomp->audio_ops, which we
> > set
> > in hdmi_codec_probe(), so we need to set it to NULL in
> > hdmi_codec_remove(),
> > otherwise we will dereference no longer existing pointer.
> 
> Hi Amadeusz,
> 
> It looks like the audio_ops should be deleted snd_hdac_acomp_exit().

It's a different one.  The codec driver registers / de-registers the
notifier at its probe/remove, while the controller driver takes care
of snd_hdac_acomp_init().  snd_hdac_acomp_exit() is usually not needed
to be called explicitly, as it's managed via devres.


Takashi

> Also, this doesnt seem to be the case with when the SOF driver is
> removed.
> Could you please give a bit more context on what error you see when
> this happens?
> 
> Thanks,
> Ranjani
> > 
> > Signed-off-by: Amadeusz Sławiński <
> > amadeuszx.slawinski@...ux.intel.com>
> > ---
> >  sound/soc/codecs/hdac_hdmi.c | 6 ++++++
> >  1 file changed, 6 insertions(+)
> > 
> > diff --git a/sound/soc/codecs/hdac_hdmi.c
> > b/sound/soc/codecs/hdac_hdmi.c
> > index 911bb6e2a1ac..9ee1bff548d8 100644
> > --- a/sound/soc/codecs/hdac_hdmi.c
> > +++ b/sound/soc/codecs/hdac_hdmi.c
> > @@ -1890,6 +1890,12 @@ static void hdmi_codec_remove(struct
> > snd_soc_component *component)
> >  {
> >  	struct hdac_hdmi_priv *hdmi =
> > snd_soc_component_get_drvdata(component);
> >  	struct hdac_device *hdev = hdmi->hdev;
> > +	int ret;
> > +
> > +	ret = snd_hdac_acomp_register_notifier(hdev->bus, NULL);
> > +	if (ret < 0)
> > +		dev_err(&hdev->dev, "notifier unregister failed: err:
> > %d\n",
> > +				ret);
> >  
> >  	pm_runtime_disable(&hdev->dev);
> >  }
> 
>