Re: [RFC] Reorganizing HD-audio driver code?

[Takashi Iwai <tiwai@suse.de>]

On Thu, 03 Jul 2025 16:32:51 +0200,
Takashi Iwai wrote:
> 
> On Thu, 03 Jul 2025 15:57:48 +0200,
> Amadeusz Sławiński wrote:
> > 
> > 
> > 
> > On 2025-07-03 15:38, Takashi Iwai wrote:
> > > On Thu, 03 Jul 2025 15:29:56 +0200,
> > > Amadeusz Sławiński wrote:
> > >> 
> > >> 
> > >> 
> > >> On 2025-07-02 16:53, Takashi Iwai wrote:
> > >>> On Sun, 29 Jun 2025 11:22:25 +0200,
> > >>> Takashi Iwai wrote:
> > >>>> 
> > >>>> On Fri, 27 Jun 2025 15:22:20 +0200,
> > >>>> Richard Fitzgerald wrote:
> > >>>>> 
> > >>>>> On 27/06/2025 1:04 pm, Takashi Iwai wrote:
> > >>>>>> Hi,
> > >>>>>> 
> > >>>>>> HD-audio driver is known to be quite messy in both file structures and
> > >>>>>> its design, but until now I haven't touched its files paths so much
> > >>>>>> because I set a higher priority for the easiness of backport to stable
> > >>>>>> kernels.  But, you can't leave garbages forever, it's been already
> > >>>>>> high time for a large clean up.
> > >>>>>> 
> > >>>>>> So I tried a quick code reorganization, and put the result in
> > >>>>>> test/hda-reorg branch of sound.git tree.
> > >>>>>>      https://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound.git/log/?h=test/hda-reorg
> > >>>>>> 
> > >>>>>> The basic idea is to move the code from sound/pci/hda/* into different
> > >>>>>> subdirectories in sound/hda/ per functionality, as most of the stuff
> > >>>>>> are independent from PCI, but rather HD-audio bus specific.
> > >>>>>> 
> > >>>>> 
> > >>>>> This all seems reasonable to me. I always thought it strange that there
> > >>>>> is a sound/hda directory but most of the HDA support isn't in that
> > >>>>> directory.
> > >>>> 
> > >>>> Thanks for your review!
> > >>>> 
> > >>>> It's a long story: at the time of ASoC Intel HD-audio support, we
> > >>>> thought to implement more ASoC-friendly way of HD-audio controller and
> > >>>> codec drivers, e.g. adapting DAPM and others.  So we began with the
> > >>>> factoring out the HD-audio basic core stuff to the common directory
> > >>>> sound/hda/*, while keeping the rest legacy stuff almost as is.  But
> > >>>> ASoC implementation didn't fly in the end from various reasons, and
> > >>>> the legacy HD-audio stuff was good enough for the actual use cases;
> > >>>> it's too bit to fail, after all.
> > >>>> 
> > >>>>>> The Realtek codec is split further to smaller pieces (which was really
> > >>>>>> huge).
> > >>>>> 
> > >>>>> Yes, that file was very confusing having support and quirks for so many
> > >>>>> Realtek parts all in one file.
> > >>>>> 
> > >>>>>> The Cirrus and TI sub-codec drivers are moved to codecs/side-codecs
> > >>>>>> subdirectory:
> > >>>>> 
> > >>>>> That's ok
> > >>>>> 
> > >>>>>> They can be put to each own directory and drop the file name prefix,
> > >>>>>> if we want, too.  Let me know if Cirrus and TI people would like to
> > >>>>>> split to more subdirectories.
> > >>>>> 
> > >>>>> I don't mind either way.
> > >>>>> The hda_component* files are common to the amps and the realtek driver
> > >>>>> so I wonder whether they belong in helpers. They are only utility
> > >>>>> wrappers around the kernel component-binding APIs.
> > >>>> 
> > >>>> Right.  So far, just because it's basically only binding with
> > >>>> side-codecs, I put into side-codecs subdirectory.
> > >>>> 
> > >>>>>> *HOWEVER* the biggest question is: whether it's worth?
> > >>>>>> 
> > >>>>>> Essentially, this makes almost impossible to make a patch for stable
> > >>>>>> trees from the original commit as is; one has to translate the file
> > >>>>>> paths and adjust manually in each patch.
> > >>>>> 
> > >>>>> Depends which file you are patching and how much it has changed.
> > >>>>> Git can figure out file renames (and changing directory is a rename).
> > >>>> 
> > >>>> I'm afraid that the Realtek codec changes might be hard to track
> > >>>> automatically.  Maybe the Cirrus side-codecs stuff would work.
> > >>>> 
> > >>>>>> Also, of course, if anyone is working on HD-audio stuff right now, the
> > >>>>>> work had to be adjusted to the new file path.  It'd be one-off action,
> > >>>>>> though.
> > >>>>> 
> > >>>>> Speaking only for Cirrus, I don't think this makes much extra effort
> > >>>>> for us. Our amp drivers have only changed location, so that should be
> > >>>>> trivial. The other file we change is patch_realtek.c but that typically
> > >>>>> is only 1-line quirk entries.
> > >>>> 
> > >>>> OK, thanks for confirmation!
> > >>> 
> > >>> ... and now I worked further on this, resulting in larger set of
> > >>> changes.  It's not only the file location changes but also the
> > >>> HD-audio codec driver binding changes.  So I put more people to Cc for
> > >>> catch their cautions.
> > >>> 
> > >>> To recap:
> > >>> 
> > >>> - The all HD-audio driver code are moved under sound/hda.
> > >>> 
> > >>>     % ls sound/hda
> > >>>     codecs/  common/  controllers/  core/  Kconfig  Makefile
> > >>> 
> > >>>     * The former hda core code is found in sound/hda/core.
> > >>>     * The former snd-hda-codec code is found in sound/hda/common.
> > >>>     * The former snd-hda-intel, tegra and acpi are put in
> > >>>       sound/hda/controllers.
> > >>>     * The former patch_* and co are put to sound/hda/codecs.
> > >>>     * Realtek codec driver is split to several modules as
> > >>>       sound/hda/codecs/realtek/alc*.
> > >>>     * Cirrus codec driver is split to cs420x and cs421x, put under
> > >>>       sound/hda/codecs/cirrus together with cs8409.
> > >>>     * HDMI codec driver is split to several modules under
> > >>>       sound/hda/codecs/hdmi
> > >>>     * Cirrus and TI sub-codecs are put under
> > >>>       sound/hda/codecs/side-codecs
> > >>> 
> > >>> - The HD-audio codec driver binding is changed from the embedded
> > >>>     hda_codec.patch_ops to hda_codec_driver.ops.
> > >>>     (As of now, hda_codec_driver.ops is a pointer, but it can be
> > >>>      embedded later, too.)
> > >>> 
> > >>>     This change required some code to be modified without the dynamic
> > >>>     override of callbacks.
> > >>> 
> > >>> - In future, we may convert the runtime PM handling to use the
> > >>>     standard pm_ops, too.  This was raised some time ago during the
> > >>>     discussion with Realtek devs.
> > >>> 
> > >>> The current patches are found in test/hda-reorg branch of sound git
> > >>> tree:
> > >>>     https://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound.git/log/?h=test/hda-reorg
> > >>> 
> > >>> It's based on master branch for taking all changes of for-linus and
> > >>> for-next, hence the branch may be still frequently rebased.
> > >>> 
> > >>> So, please let me know if you see any issues or suggestions for this
> > >>> conversion.  I have no concrete plan for merging, but if everything
> > >>> looks fine, it can be even on the next 6.17, too.
> > >>> 
> > >> 
> > >> I've built it and put it on one of our machines and hit KASAN during
> > >> HDMI initialization, when I go back to master branch it works, so it
> > >> is something on test/hda-reorg.
> > > 
> > > Yes, there was bug in my branch that I fixed in this morning.
> > > Could you try the latest test/hda-reorg branch, commit
> > > 6491d5b2e256a678b3a138500bf601c916d3913e
> > > ?
> > > 
> > 
> > Still broken :(
> 
> OK, thanks for confirmation.
> 
> I guess it's a power up code path that happens just before the codec
> driver initialization.
> 
> Could you check whether the patch below covers it?

A possible alternative is like below.  This one might be safer.
Let me know if either of them can work for you.


thanks,

Takashi

--- a/sound/hda/common/codec.c
+++ b/sound/hda/common/codec.c
@@ -2774,8 +2774,9 @@ static unsigned int hda_set_power_state(struct hda_codec *codec,
 
 	/* repeat power states setting at most 10 times*/
 	for (count = 0; count < 10; count++) {
-		/* might be called before binding to driver, too */
-		if (driver && driver->ops && driver->ops->set_power_state)
+		/* might be called before or during binding to driver, too */
+		if (device_is_bound(&codec->core.dev) &&
+		    driver && driver->ops->set_power_state)
 			driver->ops->set_power_state(codec, fg, power_state);
 		else {
 			state = power_state;