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Takashi Iwai c366b3dbba ALSA: hda - Apply sync-write workaround to old Intel platforms, too
Klaus Ethgen reported occasional high CPU usages in his system that
seem caused by HD-audio driver.  The perf output revealed that it's
in the unsolicited event handling in the workqueue, and the problem
seems triggered by some communication stall between the controller and
the codec at the runtime or system resume.

Actually a similar phenomenon was seen in the past for other Intel
platforms, and we already applied the workaround to enforce sync-write
for CORB/RIRB verbs for Skylake and newer chipsets (commit
2756d9143a "ALSA: hda - Fix intermittent CORB/RIRB stall on Intel
chips").  Fortunately, the same workaround is applicable to the old
chipset, and the experiment showed the positive effect.

Based on the experiment result, this patch enables the sync-write
workaround for all Intel chipsets.  The only reason I hesitated to
apply this workaround was about the possibly slightly higher CPU usage.
But if the lack of sync causes a much severer problem even for quite
old chip, we should think this would be necessary for all Intel chips.

Reported-by: Klaus Ethgen <Klaus@ethgen.ch>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20191223171833.GA17053@chua
Link: https://lore.kernel.org/r/20191223221816.32572-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2019-12-23 23:19:03 +01:00
arch Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-11-16 16:10:59 -08:00
block iocost: check active_list of all the ancestors in iocg_activate() 2019-11-14 13:56:54 -07:00
certs PKCS#7: Refactor verify_pkcs7_signature() 2019-08-05 18:40:18 -04:00
crypto Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-09-28 08:14:15 -07:00
Documentation ASoC: More updates for v5.5 2019-11-25 14:27:41 +01:00
drivers ASoC: More updates for v5.5 2019-11-25 14:27:41 +01:00
fs for-linus-20191115 2019-11-15 13:02:34 -08:00
include ASoC: Fixes for v5.5 2019-12-17 14:18:32 +01:00
init Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-09-28 08:14:15 -07:00
ipc ipc/sem.c: convert to use built-in RCU list checking 2019-09-25 17:51:41 -07:00
kernel Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-11-17 08:30:38 -08:00
lib lib/xz: fix XZ_DYNALLOC to avoid useless memory reallocations 2019-11-15 18:34:00 -08:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm mm/debug.c: PageAnon() is true for PageKsm() pages 2019-11-15 18:34:00 -08:00
net ipmr: Fix skb headroom in ipmr_get_route(). 2019-11-16 13:06:54 -08:00
samples samples/bpf: fix build by setting HAVE_ATTR_TEST to zero 2019-10-31 21:39:15 +01:00
scripts arm64 fix for -rc8 / final 2019-11-15 09:14:23 -08:00
security efi/efi_test: Lock down /dev/efi_test and require CAP_SYS_ADMIN 2019-10-31 09:40:21 +01:00
sound ALSA: hda - Apply sync-write workaround to old Intel platforms, too 2019-12-23 23:19:03 +01:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-11-16 15:52:00 -08:00
usr kbuild: update compile-test header list for v5.4-rc2 2019-10-05 15:29:49 +09:00
virt KVM: Add a comment describing the /dev/kvm no_compat handling 2019-11-15 10:14:04 +01:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Modules updates for v5.4 2019-09-22 10:34:46 -07:00
.mailmap ARM: SoC fixes 2019-11-10 13:41:59 -08:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS: Remove Simon as Renesas SoC Co-Maintainer 2019-10-10 08:12:51 -07:00
Kbuild kbuild: do not descend to ./Kbuild when cleaning 2019-08-21 21:03:58 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS Merge branch 'asoc-5.5' into asoc-next 2019-11-22 19:56:02 +00:00
Makefile Linux 5.4-rc8 2019-11-17 14:47:30 -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.