linux-kernel - Re: [PATCH v2 7/9] ALSA: hda/intel: Move snd_hdac_i915_init to before probe

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Message-ID: <a895de13-5320-953b-3d1c-34cee259d1d2@linux.intel.com>
Date:   Mon, 24 Jul 2023 12:58:14 +0200
From:   Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.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>,
        Cezary Rojewski <cezary.rojewski@...el.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 v2 7/9] ALSA: hda/intel: Move snd_hdac_i915_init to before
 probe_work.



On 7/19/23 18:41, 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.
> 
> Use the -EPROBE_DEFER mechanism instead, which must be returned in the
> probe function.
> 
> Changes since v1:
> - Use dev_err_probe()
> - Don't move probed_devs bitmap unnecessarily. (tiwai)
> - Move snd_hdac_i915_init slightly upward, to ensure
>   it's always initialised before vga-switcheroo is called.
> 
> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>
> ---
>  sound/pci/hda/hda_intel.c | 59 ++++++++++++++++++++-------------------
>  1 file changed, 30 insertions(+), 29 deletions(-)
> 
> diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
> index 11cf9907f039f..e3128d7d742e7 100644
> --- a/sound/pci/hda/hda_intel.c
> +++ b/sound/pci/hda/hda_intel.c
> @@ -2147,6 +2147,36 @@ static int azx_probe(struct pci_dev *pci,
>  
>  	pci_set_drvdata(pci, card);
>  
> +#ifdef CONFIG_SND_HDA_I915
> +	/* bind with i915 if needed */
> +	if (chip->driver_caps & AZX_DCAPS_I915_COMPONENT) {
> +		err = snd_hdac_i915_init(azx_bus(chip), false);
> +		if (err < 0) {
> +			/* if the controller is bound only with HDMI/DP
> +			 * (for HSW and BDW), we need to abort the probe;
> +			 * for other chips, still continue probing as other
> +			 * codecs can be on the same link.
> +			 */
> +			if (CONTROLLER_IN_GPU(pci)) {
> +				dev_err_probe(card->dev, err,
> +					     "HSW/BDW HD-audio HDMI/DP requires binding with gfx driver\n");
> +
> +				goto out_free;
> +			} else {
> +				/* don't bother any longer */
> +				chip->driver_caps &= ~AZX_DCAPS_I915_COMPONENT;
> +			}
> +		}
> +
> +		/* HSW/BDW controllers need this power */
> +		if (CONTROLLER_IN_GPU(pci))
> +			hda->need_i915_power = true;
> +	}
> +#else
> +	if (CONTROLLER_IN_GPU(pci))
> +		dev_err(card->dev, "Haswell/Broadwell HDMI/DP must build in CONFIG_SND_HDA_I915\n");
> +#endif

Is it intentional that the display_power() is left in the probe workqueue?

this piece of code follows the stuff above in the existing code?

/* Request display power well for the HDA controller or codec. For
 * Haswell/Broadwell, both the display HDA controller and codec need
 * this power. For other platforms, like Baytrail/Braswell, only the
 * display codec needs the power and it can be released after probe.
 */
display_power(chip, true);



> +
>  	err = register_vga_switcheroo(chip);
>  	if (err < 0) {
>  		dev_err(card->dev, "Error registering vga_switcheroo client\n");
> @@ -2174,11 +2204,6 @@ static int azx_probe(struct pci_dev *pci,
>  	}
>  #endif /* CONFIG_SND_HDA_PATCH_LOADER */
>  
> -#ifndef CONFIG_SND_HDA_I915
> -	if (CONTROLLER_IN_GPU(pci))
> -		dev_err(card->dev, "Haswell/Broadwell HDMI/DP must build in CONFIG_SND_HDA_I915\n");
> -#endif
> -
>  	if (schedule_probe)
>  		schedule_delayed_work(&hda->probe_work, 0);
>  
> @@ -2275,30 +2300,6 @@ static int azx_probe_continue(struct azx *chip)
>  	to_hda_bus(bus)->bus_probing = 1;
>  	hda->probe_continued = 1;
>  
> -	/* bind with i915 if needed */
> -	if (chip->driver_caps & AZX_DCAPS_I915_COMPONENT) {
> -		err = snd_hdac_i915_init(bus, true);
> -		if (err < 0) {
> -			/* if the controller is bound only with HDMI/DP
> -			 * (for HSW and BDW), we need to abort the probe;
> -			 * for other chips, still continue probing as other
> -			 * codecs can be on the same link.
> -			 */
> -			if (CONTROLLER_IN_GPU(pci)) {
> -				dev_err(chip->card->dev,
> -					"HSW/BDW HD-audio HDMI/DP requires binding with gfx driver\n");
> -				goto out_free;
> -			} else {
> -				/* don't bother any longer */
> -				chip->driver_caps &= ~AZX_DCAPS_I915_COMPONENT;
> -			}
> -		}
> -
> -		/* HSW/BDW controllers need this power */
> -		if (CONTROLLER_IN_GPU(pci))
> -			hda->need_i915_power = true;
> -	}
> -
>  	/* Request display power well for the HDA controller or codec. For
>  	 * Haswell/Broadwell, both the display HDA controller and codec need
>  	 * this power. For other platforms, like Baytrail/Braswell, only the