linux-kernel - Re: [PATCH 3/7] ASoC: Intel: avs: Move snd_hdac_i915_init to before probe

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Date:   Wed, 19 Jul 2023 17:26:24 +0200
From:   Cezary Rojewski <cezary.rojewski@...el.com>
To:     Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        <alsa-devel@...a-project.org>
CC:     <sound-open-firmware@...a-project.org>,
        <linux-kernel@...r.kernel.org>, Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>,
        "Pierre-Louis Bossart" <pierre-louis.bossart@...ux.intel.com>,
        Liam Girdwood <liam.r.girdwood@...ux.intel.com>,
        Peter Ujfalusi <peter.ujfalusi@...ux.intel.com>,
        Bard Liao <yung-chuan.liao@...ux.intel.com>,
        Ranjani Sridharan <ranjani.sridharan@...ux.intel.com>,
        Kai Vehmanen <kai.vehmanen@...ux.intel.com>,
        Mark Brown <broonie@...nel.org>,
        "Daniel Baluta" <daniel.baluta@....com>
Subject: Re: [PATCH 3/7] ASoC: Intel: avs: Move snd_hdac_i915_init to before
 probe_work.

On 2023-07-18 10:45 AM, Maarten Lankhorst wrote:
> Now that we can use -EPROBE_DEFER, it's no longer required to spin off
> the snd_hdac_i915_init into a workqueue. It's likely the whole workqueue
> can be destroyed, but I don't have the means to test this.
> 
> Removing the workqueue would simplify init even further, but is left
> as exercise for the reviewer.
> 
> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>
> ---
>   sound/soc/intel/avs/core.c | 13 +++++++++----
>   1 file changed, 9 insertions(+), 4 deletions(-)
> 
> diff --git a/sound/soc/intel/avs/core.c b/sound/soc/intel/avs/core.c
> index 3311a6f142001..d3a7f42387e9b 100644
> --- a/sound/soc/intel/avs/core.c
> +++ b/sound/soc/intel/avs/core.c
> @@ -191,10 +191,6 @@ static void avs_hda_probe_work(struct work_struct *work)
>   
>   	pm_runtime_set_active(bus->dev); /* clear runtime_error flag */
>   
> -	ret = snd_hdac_i915_init(bus, true);
> -	if (ret < 0)
> -		dev_info(bus->dev, "i915 init unsuccessful: %d\n", ret);
> -
>   	snd_hdac_display_power(bus, HDA_CODEC_IDX_CONTROLLER, true);
>   	avs_hdac_bus_init_chip(bus, true);
>   	avs_hdac_bus_probe_codecs(bus);
> @@ -465,10 +461,19 @@ static int avs_pci_probe(struct pci_dev *pci, const struct pci_device_id *id)
>   	pci_set_drvdata(pci, bus);
>   	device_disable_async_suspend(dev);
>   
> +	ret = snd_hdac_i915_init(bus, false);
> +	if (ret == -EPROBE_DEFER)
> +		goto err_unmaster;
> +	else if (ret < 0)
> +		dev_info(bus->dev, "i915 init unsuccessful: %d\n", ret);
> +

While our tests are currently passing I have my doubts about 
EPROBE_DEFER. We do want to have audio functionality there even if some 
problems with HDMI arise along the way - some audio is better than no 
audio. Here, i915 may ruin the day for a platform equipped with 
hda/hdmi/i2c/dmic chips simultaneously.

Also, why call snd_hdac_i915_init() _after_ setting drvdata?

>   	schedule_work(&adev->probe_work);
>   
>   	return 0;
>   
> +err_unmaster:
> +	pci_clear_master(pci);
> +	pci_set_drvdata(pci, NULL);

Not a fan. It's hard to grasp entire error-step within name of a single 
label. Thus I'd suggest "err_<cause>" naming pattern instead. Even here, 
under "unmaster" you hid clearing master and drvdata both. Let's do 
"err_i915_init" instead.

>   err_acquire_irq:
>   	snd_hdac_bus_free_stream_pages(bus);
>   	snd_hdac_ext_stream_free_all(bus);