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Rafael J. Wysocki be1fcde604 x86: intel_epb: Do not build when CONFIG_PM is unset
Commit 9ed0985332 ("x86: intel_epb: Take CONFIG_PM into account")
prevented the majority of the Performance and Energy Bias Hint (EPB)
handling code from being built when CONFIG_PM is unset to fix a
regression introduced by commit b9c273babc ("PM / arch: x86:
MSR_IA32_ENERGY_PERF_BIAS sysfs interface").

In hindsight, however, it would be better to skip all of the EPB
handling code for CONFIG_PM unset as there really is no reason for
it to be there in that case.  Namely, if the EPB is not touched
by the kernel at all with CONFIG_PM unset, there is no need to
worry about modifying the EPB inadvertently on CPU online and since
the system will not suspend or hibernate then, there is no need to
worry about possible modifications of the EPB by the platform
firmware during system-wide PM transitions.

For this reason, revert the changes made by commit 9ed0985332
and only allow intel_epb.o to be built when CONFIG_PM is set.

Note that this changes the behavior of the kernels built with
CONFIG_PM unset as they will not modify the EPB on boot if it is
zero initially any more, so it is not a fix strictly speaking, but
users building their kernels with CONFIG_PM unset really should not
expect them to take energy efficiency into account.  Moreover, if
CONFIG_PM is unset for performance reasons, leaving EPB as set
initially by the platform firmware will actually be consistent
with the user's expectations.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
2019-05-30 10:58:36 +02:00
Documentation Devicetree fixes for 5.2: 2019-05-24 15:16:46 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
arch x86: intel_epb: Do not build when CONFIG_PM is unset 2019-05-30 10:58:36 +02:00
block blk-mq: fix hang caused by freeze/unfreeze sequence 2019-05-23 10:25:26 -06:00
certs treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36 2019-05-24 17:27:11 +02:00
crypto treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 102 2019-05-24 17:39:00 +02:00
drivers Fix a soft lockup regression when reading from /dev/random in early boot 2019-05-26 08:30:16 -07:00
fs Bug fixes (including a regression fix) for ext4. 2019-05-25 15:03:12 -07:00
include libnvdimm fixes v5.2-rc2 2019-05-25 10:11:23 -07:00
init treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
ipc treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 52 2019-05-24 17:36:42 +02:00
kernel Make the GCC 9 warning for sub struct memset go away. 2019-05-26 13:49:40 -07:00
lib for-linus-20190524 2019-05-24 16:02:14 -07:00
mm treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 98 2019-05-24 17:37:54 +02:00
net SPDX update for 5.2-rc2, round 2 2019-05-24 14:31:58 -07:00
samples treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36 2019-05-24 17:27:11 +02:00
scripts Devicetree fixes for 5.2: 2019-05-24 15:16:46 -07:00
security SPDX update for 5.2-rc2, round 2 2019-05-24 14:31:58 -07:00
sound treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 119 2019-05-24 17:39:02 +02:00
tools The usual smattering of fixes and tunings that came in too late for the 2019-05-26 13:45:15 -07:00
usr user/Makefile: Fix typo and capitalization in comment section 2018-12-11 00:18:03 +09:00
virt The usual smattering of fixes and tunings that came in too late for the 2019-05-26 13:45:15 -07:00
.clang-format Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-04-17 11:26:25 -07:00
.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: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore .gitignore: exclude .get_maintainer.ignore and .gitattributes 2019-05-18 11:49:54 +09:00
.mailmap A reasonably busy cycle for docs, including: 2019-05-08 12:42:50 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS Char/Misc driver patches for 5.1-rc1 2019-03-06 14:18:59 -08:00
Kbuild Kbuild updates for v5.1 2019-03-10 17:48:21 -07:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS The usual smattering of fixes and tunings that came in too late for the 2019-05-26 13:45:15 -07:00
Makefile Linux 5.2-rc2 2019-05-26 16:49:19 -07:00
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.