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Takashi Iwai b96681bd58 ALSA: usb-audio: Initialize every feature unit once at probe time
So far we used to read the current value of the mixer element
dynamically at the first access, and the error from a GET_CUR message
is treated as a fatal error (unless QUIRK_IGNORE_CTL_ERROR is set).
It's rather inconvenient, as most of GET_CUR errors are no fatal, and
we can continue operation with assumption of some fixed value.

This patch makes the USB-audio driver to change the behavior at probe
time; now it tries to initialize the current value of each mixer
element that is built from a feature unit (those for typically for
mixer volumes and switches).  When a read failure happens, it tries to
set the known minimum value.  After that point, a cached value is used
always, hence we won't hit GET_CUR message error any longer.

The error from GET_CUR message is still shown as a warning normally,
but only once at the probe time, and it'll keep operating.  If the
message is confirmed to be harmless, it can be shut up by
QUIRK_IGNORE_CTL_ERROR quirk flag, too.

Tested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20211014130636.17860-4-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2021-10-14 16:51:56 +02:00
arch Updates for the SMP and CPU hotplug: 2021-09-12 12:42:51 -07:00
block block-5.15-2021-09-11 2021-09-11 10:19:51 -07:00
certs certs: Add support for using elliptic curve keys for signing modules 2021-08-23 19:55:42 +03:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2021-08-30 12:57:10 -07:00
Documentation An assortment of improvements for auxdisplay: 2021-09-12 16:00:49 -07:00
drivers An assortment of improvements for auxdisplay: 2021-09-12 16:00:49 -07:00
fs Merge branch 'misc.namei' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2021-09-12 10:43:51 -07:00
include Merge branch 'for-linus' into for-next 2021-10-14 15:54:30 +02:00
init More tracing updates for 5.15: 2021-09-09 13:11:15 -07:00
ipc ARM development updates for 5.15: 2021-09-09 13:25:49 -07:00
kernel - Make sure the idle timer expires in hardirq context, on PREEMPT_RT 2021-09-12 11:37:41 -07:00
lib Minor fixes to the processing of the bootconfig tree. 2021-09-11 10:16:30 -07:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
mm ARM development updates for 5.15: 2021-09-09 13:25:49 -07:00
net virtio,vdpa,vhost: features, fixes 2021-09-11 14:48:42 -07:00
samples kgdb patches for 5.15 2021-09-07 12:08:04 -07:00
scripts RISC-V Patches for the 5.15 Merge Window, Part 2 2021-09-11 14:29:42 -07:00
security Kbuild updates for v5.15 2021-09-03 15:33:47 -07:00
sound ALSA: usb-audio: Initialize every feature unit once at probe time 2021-10-14 16:51:56 +02:00
tools perf tools changes for v5.15: 2nd batch 2021-09-12 16:18:15 -07:00
usr .gitignore: prefix local generated files with a slash 2021-05-02 00:43:35 +09:00
virt KVM: Drop unused kvm_dirty_gfn_invalid() 2021-09-06 08:23:46 -04:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: update email address of Matthias Fuchs and Thomas Körper 2021-08-19 09:39:44 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: move Murali Karicheri to credits 2021-04-29 15:47:30 -07:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS ASoC: Fixes for v5.15 2021-09-21 18:42:14 +02:00
Makefile Linux 5.15-rc1 2021-09-12 16:28:37 -07:00
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.