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Giacomo Guiduzzi c2052ad0c7 ALSA: pci: fix reading of swapped values from pcmreg in AC97 codec
commit 17aaf01933 upstream.

Tests 72 and 78 for ALSA in kselftest fail due to reading
inconsistent values from some devices on a VirtualBox
Virtual Machine using the snd_intel8x0 driver for the AC'97
Audio Controller device.
Taking for example test number 72, this is what the test reports:
"Surround Playback Volume.0 expected 1 but read 0, is_volatile 0"
"Surround Playback Volume.1 expected 0 but read 1, is_volatile 0"
These errors repeat for each value from 0 to 31.

Taking a look at these error messages it is possible to notice
that the written values are read back swapped.
When the write is performed, these values are initially stored in
an array used to sanity-check them and write them in the pcmreg
array. To write them, the two one-byte values are packed together
in a two-byte variable through bitwise operations: the first
value is shifted left by one byte and the second value is stored in the
right byte through a bitwise OR. When reading the values back,
right shifts are performed to retrieve the previously stored
bytes. These shifts are executed in the wrong order, thus
reporting the values swapped as shown above.

This patch fixes this mistake by reversing the read
operations' order.

Signed-off-by: Giacomo Guiduzzi <guiduzzi.giacomo@gmail.com>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220322200653.15862-1-guiduzzi.giacomo@gmail.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-28 09:58:44 +02:00
Documentation swiotlb: rework "fix info leak with DMA_FROM_DEVICE" 2022-03-16 14:23:43 +01:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
arch arm64: fix clang warning about TRAMP_VALIAS 2022-03-23 09:16:43 +01:00
block block: release rq qos structures for queue without disk 2022-03-23 09:16:41 +01:00
certs certs: Add support for using elliptic curve keys for signing modules 2021-08-23 19:55:42 +03:00
crypto crypto: api - Move cryptomgr soft dependency into algapi 2022-02-11 09:10:26 +01:00
drivers Bluetooth: btusb: Add another Realtek 8761BU 2022-03-28 09:58:42 +02:00
fs btrfs: skip reserved bytes warning on unmount after log cleanup failure 2022-03-23 09:16:43 +01:00
include ALSA: pcm: Fix races among concurrent hw_params and hw_free calls 2022-03-28 09:58:43 +02:00
init init: make unknown command line param message clearer 2021-11-18 19:17:11 +01:00
ipc ipc/sem: do not sleep with a spin lock held 2022-02-08 18:34:03 +01:00
kernel watch_queue: Make comment about setting ->defunct more accurate 2022-03-16 14:23:45 +01:00
lib ARM: 9178/1: fix unmet dependency on BITREVERSE for HAVE_ARCH_BITREVERSE 2022-03-19 13:47:48 +01:00
mm mm: swap: get rid of livelock in swapin readahead 2022-03-23 09:16:41 +01:00
net llc: fix netdevice reference leaks in llc_ui_bind() 2022-03-28 09:58:42 +02:00
samples samples: bpf: Fix 'unknown warning group' build warning on Clang 2022-01-27 11:03:29 +01:00
scripts kconfig: fix failing to generate auto.conf 2022-02-23 12:03:20 +01:00
security selinux: fix misuse of mutex_is_locked() 2022-03-02 11:47:48 +01:00
sound ALSA: pci: fix reading of swapped values from pcmreg in AC97 codec 2022-03-28 09:58:44 +02:00
tools perf symbols: Fix symbol size calculation condition 2022-03-23 09:16:43 +01:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2022-02-01 17:27:15 +01:00
virt KVM: Fix lockdep false negative during host resume 2022-03-16 14:23:40 +01:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.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: add Andrej Shadura 2021-10-18 20:22:03 -10:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
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 MAINTAINERS: adjust file entry for of_net.c after movement 2022-03-08 19:12:53 +01:00
Makefile Linux 5.15.31 2022-03-23 09:16:44 +01:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.