kernel/include/sound/pcm.h, branch linux-5.2.y

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156

2019-05-30T18:26:35Z

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation inc 59 temple place suite 330 boston ma 02111 1307 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 1334 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Reviewed-by: Richard Fontana Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de Signed-off-by: Greg Kroah-Hartman

ALSA: pcm: Fix function name in kernel-doc comment

2019-03-13T20:26:32Z

Signed-off-by: Ricardo Biehl Pasquali Signed-off-by: Takashi Iwai

ALSA: pcm: Define snd_pcm_lib_preallocate_*() as returning void

2019-02-08T13:24:12Z

Now all callers no longer check the return value from snd_pcm_lib_preallocate_pages() and co, let's make them to return void, so that any new code won't fall into the same pitfall. Reviewed-by: Jaroslav Kysela Signed-off-by: Takashi Iwai

Merge branch 'topic/pcm-lock-refactor' into for-next

2019-01-24T13:46:21Z

Pull PCM lock refactoring. Signed-off-by: Takashi Iwai

ALSA: pcm: Simplify proc file destruction

2019-01-24T13:40:25Z

The proc files are recursively freed by calling with the root snd_info_entry object, so we don't have to keep each object for releasing one by one. Move the release of the PCM stream proc root at the beginning, so that we can remove the redundant code and resource. Signed-off-by: Takashi Iwai

ALSA: pcm: Drop unused snd_pcm_substream.file field

2019-01-24T13:40:25Z

It's assigned but nowhere used. Let's remove it. Signed-off-by: Takashi Iwai

ALSA: pcm: More fine-grained PCM link locking

2019-01-23T06:25:08Z

We have currently two global locks, a rwlock and a rwsem, that are used for managing linking the PCM streams. Due to these global locks, once when a linked stream is used, the lock granularity suffers a lot. This patch attempts to eliminate the former global lock for atomic ops. The latter rwsem needs remaining because of the loosy way of the loop calls in snd_pcm_action_nonatomic(), as well as for avoiding the deadlock at linking. However, these are used far rarely, actually only by two actions (prepare and reset), where both are no timing critical ones. So this can be still seen as a good improvement. The basic strategy to eliminate the rwlock is to assure group->lock at adding or removing a stream to / from the group. Since we already takes the group lock whenever taking the all substream locks under the group, this shouldn't be a big problem. The reference to group pointer in snd_pcm_substream object is protected by the stream lock itself. However, there are still pitfalls: a race window at re-locking and the lifecycle of group object. The former is a small race window for dereferencing the substream group object opened while snd_pcm_action() performs re-locking to avoid ABBA deadlocks. This includes the unlink of group during that window, too. And the latter is the kfree performed after all streams are removed from the group while it's still dereferenced. For addressing these corner cases, two new tricks are introduced: - After re-locking, the group assigned to the stream is checked again; if the group is changed, we retry the whole procedure. - Introduce a refcount to snd_pcm_group object, so that it's freed only when it's empty and really no one refers to it. (Some readers might wonder why not RCU for the latter. RCU in this case would cost more than refcounting, unfortunately. We take the group lock sooner or later, hence the performance improvement by RCU would be negligible. Meanwhile, because we need to deal with schedulable context depending on the pcm->nonatomic flag, it'll become dynamic RCU/SRCU switch, and the grace period may become too long.) Along with these changes, there are a significant amount of code refactoring. The complex group re-lock & ref code is factored out to snd_pcm_stream_group_ref() function, for example. Signed-off-by: Takashi Iwai

ALSA: pcm: Make PCM linked list consistent while re-grouping

2019-01-21T15:39:54Z

Make a common helper to re-assign the PCM link using list_move() instead of open code with manual list_del() and list_add_tail(). This assures the consistency and we can get rid of snd_pcm_group.count field -- its purpose is only to check whether the list is singular, and we can know it by list_is_singular() call now. Signed-off-by: Takashi Iwai

ALSA: pcm: Make snd_pcm_suspend() local static

2019-01-15T16:48:23Z

snd_pcm_suspend() is no longer called from outside, so let's make it local static. Also drop a superfluous NULL check there. Reviewed-by: Jaroslav Kysela Signed-off-by: Takashi Iwai

ALSA: pcm: Suspend streams globally via device type PM ops

2019-01-15T16:46:36Z

Until now we rely on each driver calling snd_pcm_suspend*() explicitly at its own PM handling. However, this can be done far more easily by setting the PM ops to each actual snd_pcm device object. This patch adds the device_type object for PCM stream and assigns to each PCM stream object. The type contains only the PM ops for system suspend; we don't need to deal with the resume in general. The suspend hook simply calls snd_pcm_suspend_all() for the given PCM streams. This implies that the PM order is correctly put, i.e. PCM is suspended before the main (or codec) driver, which should be true in general. If a special ordering is needed, you'd need to adjust the device PM order manually later. This patch introduces a new flag, snd_pcm.no_device_suspend, too. With this flag set, the PCM device object won't invoke snd_pcm_suspend_all() by itself. This is needed for ASoC who wants to manage the PM call orders in its serialized way, and the flag is set in soc_new_pcm() as default. For the non-ASoC world, we can get rid of the manual snd_pcm_suspend calls. This will be done in the later patches. Reviewed-by: Jaroslav Kysela Signed-off-by: Takashi Iwai