Re: [PATCH v2 0/9] sound: Use -EPROBE_DEFER instead of i915 module loading.

[Péter Ujfalusi]

Hi Maarten,

On 19/07/2023 19:41, 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.

Apart from the few comments I had, this looks great and works OK on the
machines I have tested (iow, no regression so far).

Thank you for the work!
-- 
Péter

> 
> ---
> New since first version:
> 
> - snd_hda_core.gpu_bind is added as a mechanism to force gpu binding,
>   for testing. snd_hda_core.gpu_bind=0 forces waiting for GPU bind to
>   off, snd_hda_core.gpu_bind=1 forces waiting for gpu bind. Default
>   setting depends on whether kernel booted with nomodeset.
> - Incorporated all feedback review.
> 
> Cc: Jaroslav Kysela <perex@xxxxxxxx>
> Cc: Takashi Iwai <tiwai@xxxxxxxx>
> Cc: Cezary Rojewski <cezary.rojewski@xxxxxxxxx>
> Cc: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
> Cc: Liam Girdwood <liam.r.girdwood@xxxxxxxxxxxxxxx>
> Cc: Peter Ujfalusi <peter.ujfalusi@xxxxxxxxxxxxxxx>
> Cc: Bard Liao <yung-chuan.liao@xxxxxxxxxxxxxxx>
> Cc: Ranjani Sridharan <ranjani.sridharan@xxxxxxxxxxxxxxx>
> Cc: Kai Vehmanen <kai.vehmanen@xxxxxxxxxxxxxxx>
> Cc: Mark Brown <broonie@xxxxxxxxxx>
> Cc: Daniel Baluta <daniel.baluta@xxxxxxx>
> Cc: alsa-devel@xxxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Cc: sound-open-firmware@xxxxxxxxxxxxxxxx
> 
> Maarten Lankhorst (9):
>   ALSA: hda/intel: Fix error handling in azx_probe()
>   ALSA: hda/i915: Allow override of gpu binding.
>   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
> 
>  sound/hda/hdac_i915.c         | 25 ++++++++-------
>  sound/pci/hda/hda_intel.c     | 60 ++++++++++++++++++-----------------
>  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, 85 insertions(+), 142 deletions(-)
>