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0ced7b0502
soc-topology adds extra dai_link by using snd_soc_add_dai_link(),
and removes it by snd_soc_romove_dai_link().
This snd_soc_add/remove_dai_link() and/or its related
functions are unbalanced before, and now, these are balance-uped.
But, it finds the random operation issue, and it is reported by
Pierre-Louis.
When card was released, topology will call snd_soc_remove_dai_link()
via (A).
static void soc_cleanup_card_resources(struct snd_soc_card *card)
{
struct snd_soc_dai_link *link, *_link;
/* This should be called before snd_card_free() */
(A) soc_remove_link_components(card);
/* free the ALSA card at first; this syncs with pending operations */
if (card->snd_card) {
(B) snd_card_free(card->snd_card);
card->snd_card = NULL;
}
/* remove and free each DAI */
(X) soc_remove_link_dais(card);
for_each_card_links_safe(card, link, _link)
(C) snd_soc_remove_dai_link(card, link);
...
}
At (A), topology calls snd_soc_remove_dai_link().
Then topology rtd, and its related all data are freed.
Next, (B) is called, and then, pcm->private_free = soc_pcm_private_free()
is called.
static void soc_pcm_private_free(struct snd_pcm *pcm)
{
struct snd_soc_pcm_runtime *rtd = pcm->private_data;
/* need to sync the delayed work before releasing resources */
flush_delayed_work(&rtd->delayed_work);
snd_soc_pcm_component_free(rtd);
}
Here, it gets rtd via pcm->private_data.
But, topology related rtd are already freed at (A).
Normal sound card has no damage, becase it frees rtd at (C).
These are finalizing rtd related data.
Thus, these should be called when rtd was freed, not sound card
was freed. It is very natural and understandable.
In other words, pcm->private_free = soc_pcm_private_free()
is no longer needed.
Extra issue is that there is zero chance to call
soc_remove_dai() for topology related dai at (X).
Because (A) removes rtd connection from card too, and,
(X) is based on card connected rtd.
This means, (X) need to be called before (C) (= for normal sound)
and (A) (= for topology).
Now, I want to focus this patch which is the reason why
snd_card_free() = (B) is located there.
commit
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.