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Takashi Iwai a4aad5636c ALSA: usb-audio: Inform devices that need delayed registration
The USB-audio driver may call snd_card_register() multiple times as
its probe function is per USB interface while some USB-audio devices
may provide multiple interfaces to assign different streams although
they belong to the same device.  This works in most cases but the
registration is racy, hence it may miss the device recognition,
e.g. PA doesn't see certain devices when hotplugged.

The recent addition of the delayed registration quirk allows to sync
the registration at the last known interface, and the previous commit
added a new module option to allow the dynamic setup for that
purpose.

Now, this patch tries to find out and notifies for such devices that
require the delayed registration.  It shows a message like:

  Found post-registration device assignment: 1234abcd:02

If you hit this message, you can pass delayed_register module option
like:

  snd_usb_audio.delayed_register=1234abcd:02

by just copying the last shown entry.  If this works, it can be added
statically in the quirk list, registration_quirks[] found at the end
of sound/usb/quirks.c.

Link: https://lore.kernel.org/r/20200325103322.2508-4-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2020-03-26 10:49:08 +01:00
arch Kbuild updates for v5.6 (2nd) 2020-02-09 16:05:50 -08:00
block block-5.6-2020-02-05 2020-02-06 06:15:23 +00:00
certs certs: Add wrapper function to check blacklisted binary hash 2019-11-12 12:25:50 +11:00
crypto treewide: remove redundant IS_ERR() before error code check 2020-02-04 03:05:27 +00:00
Documentation Kbuild updates for v5.6 (2nd) 2020-02-09 16:05:50 -08:00
drivers Kbuild updates for v5.6 (2nd) 2020-02-09 16:05:50 -08:00
fs Kbuild updates for v5.6 (2nd) 2020-02-09 16:05:50 -08:00
include ALSA: core: Add snd_device_get_state() helper 2020-03-23 18:09:19 +01:00
init Tracing updates: 2020-02-06 07:12:11 +00:00
ipc proc: convert everything to "struct proc_ops" 2020-02-04 03:05:26 +00:00
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LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
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security Merge branch 'merge.nfs-fs_parse.1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-02-08 13:26:41 -08:00
sound ALSA: usb-audio: Inform devices that need delayed registration 2020-03-26 10:49:08 +01:00
tools A set of fixes and improvements for the perf subsystem: 2020-02-09 12:04:09 -08:00
usr Kbuild updates for v5.6 (2nd) 2020-02-09 16:05:50 -08:00
virt KVM: fix overflow of zero page refcount with ksm running 2020-02-05 15:27:46 +01:00
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.mailmap A handful of small documentation fixes that wandered in. 2020-02-07 13:03:10 -08:00
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CREDITS open: introduce openat2(2) syscall 2020-01-18 09:19:18 -05:00
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Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS fs: New zonefs file system 2020-02-09 15:51:46 -08:00
Makefile Linux 5.6-rc1 2020-02-09 16:08:48 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.