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Date:   Tue, 18 Jul 2023 11:50:24 +0200
Message-ID: <87ilaho8f3.wl-tiwai@suse.de>
From:   Takashi Iwai <tiwai@suse.de>
To:     Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc:     alsa-devel@alsa-project.org, sound-open-firmware@alsa-project.org,
        linux-kernel@vger.kernel.org, Jaroslav Kysela <perex@perex.cz>,
        Takashi Iwai <tiwai@suse.com>,
        Cezary Rojewski <cezary.rojewski@intel.com>,
        Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>,
        Liam Girdwood <liam.r.girdwood@linux.intel.com>,
        Peter Ujfalusi <peter.ujfalusi@linux.intel.com>,
        Bard Liao <yung-chuan.liao@linux.intel.com>,
        Ranjani Sridharan <ranjani.sridharan@linux.intel.com>,
        Kai Vehmanen <kai.vehmanen@linux.intel.com>,
        Mark Brown <broonie@kernel.org>,
        Daniel Baluta <daniel.baluta@nxp.com>
Subject: Re: [PATCH 0/7] sound: Use -EPROBE_DEFER instead of i915 module loading.
In-Reply-To: <20230718084522.116952-1-maarten.lankhorst@linux.intel.com>
References: <20230718084522.116952-1-maarten.lankhorst@linux.intel.com>
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On Tue, 18 Jul 2023 10:45:15 +0200,
Maarten Lankhorst wrote:
> 
> Explicitly loading i915 becomes a problem when upstreaming the new intel driver
> for Tiger Lake and higher graphics (xe). By loading i915, it doesn't wait for
> driver load of xe, and will fail completely before it loads.
> 
> -EPROBE_DEFER has to be returned before any device is created in probe(),
> otherwise the removal of the device will cause EPROBE_DEFER to try again
> in an infinite loop.
> 
> The conversion is done in gradual steps. First I add an argument to
> snd_hdac_i915_init to allow for -EPROBE_DEFER so I can convert each driver
> separately. Then I convert each driver to move snd_hdac_i915_init out of the
> workqueue. Finally I drop the ability to choose modprobe behavior after the
> last user is converted.
> 
> I suspect the avs and skylake drivers used snd_hdac_i915_init purely for the
> modprobe, but I don't have the hardware to test if it can be safely removed.
> It can still be done easily in a followup patch to simplify probing.

Thanks for the patches.  I naively thought that issuing the component
binding at the early stage could be problematic, but in this case,
this doesn't look OK, since the all i915 stuff is bound always at the
HD-audio controller level, not at the codec level like others.

So, it's definitely worth to try.


Takashi

> Maarten Lankhorst (7):
>   ALSA: hda/i915: Add an allow_modprobe argument to snd_hdac_i915_init
>   ALSA: hda/i915: Allow xe as match for i915_component_master_match
>   ASoC: Intel: avs: Move snd_hdac_i915_init to before probe_work.
>   ASoC: Intel: Skylake: Move snd_hdac_i915_init to before probe_work.
>   ALSA: hda/intel: Move snd_hdac_i915_init to before probe_work.
>   ASoC: SOF: Intel: Remove deferred probe for SOF
>   ALSA: hda/i915: Remove extra argument from snd_hdac_i915_init
> 
> Cc: Jaroslav Kysela <perex@perex.cz>
> Cc: Takashi Iwai <tiwai@suse.com>
> Cc: Cezary Rojewski <cezary.rojewski@intel.com>
> Cc: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
> Cc: Liam Girdwood <liam.r.girdwood@linux.intel.com>
> Cc: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
> Cc: Bard Liao <yung-chuan.liao@linux.intel.com>
> Cc: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
> Cc: Kai Vehmanen <kai.vehmanen@linux.intel.com>
> Cc: Mark Brown <broonie@kernel.org>
> Cc: Daniel Baluta <daniel.baluta@nxp.com>
> Cc: alsa-devel@alsa-project.org
> Cc: linux-kernel@vger.kernel.org
> Cc: sound-open-firmware@alsa-project.org
> 
>  sound/hda/hdac_i915.c         | 15 +++------
>  sound/pci/hda/hda_intel.c     | 58 +++++++++++++++++++----------------
>  sound/soc/intel/avs/core.c    | 13 +++++---
>  sound/soc/intel/skylake/skl.c | 31 ++++++-------------
>  sound/soc/sof/Kconfig         | 19 ------------
>  sound/soc/sof/core.c          | 38 ++---------------------
>  sound/soc/sof/intel/Kconfig   |  1 -
>  sound/soc/sof/intel/hda.c     | 32 +++++++++++--------
>  sound/soc/sof/sof-pci-dev.c   |  3 +-
>  sound/soc/sof/sof-priv.h      |  5 ---
>  10 files changed, 75 insertions(+), 140 deletions(-)
> 
> -- 
> 2.39.2
>