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Pali Rohár bee54028ce PCI: aardvark: Don't blindly enable ASPM L0s and don't write to read-only register
[ Upstream commit 90c6cb4a35 ]

Trying to change Link Status register does not have any effect as this
is a read-only register. Trying to overwrite bits for Negotiated Link
Width does not make sense.

In future proper change of link width can be done via Lane Count Select
bits in PCIe Control 0 register.

Trying to unconditionally enable ASPM L0s via ASPM Control bits in Link
Control register is wrong. There should be at least some detection if
endpoint supports L0s as isn't mandatory.

Moreover ASPM Control bits in Link Control register are controlled by
pcie/aspm.c code which sets it according to system ASPM settings,
immediately after aardvark driver probes. So setting these bits by
aardvark driver has no long running effect.

Remove code which touches ASPM L0s bits from this driver and let
kernel's ASPM implementation to set ASPM state properly.

Some users are reporting issues that this code is problematic for some
Intel wifi cards and removing it fixes them, see e.g.:
https://bugzilla.kernel.org/show_bug.cgi?id=196339

If problems with Intel wifi cards occur even after this commit, then
pcie/aspm.c code could be modified / hooked to not enable ASPM L0s state
for affected problematic cards.

Link: https://lore.kernel.org/r/20200430080625.26070-3-pali@kernel.org
Tested-by: Tomasz Maciej Nowak <tmn505@gmail.com>
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-06-25 15:32:49 +02:00
arch ARM: integrator: Add some Kconfig selections 2020-06-25 15:32:48 +02:00
block block, bfq: fix use-after-free in bfq_idle_slice_timer_body 2020-04-17 10:48:42 +02:00
certs export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR() 2018-08-22 23:21:44 +09:00
crypto gcc-10: avoid shadowing standard library 'free()' in crypto 2020-05-20 08:18:46 +02:00
Documentation dt-bindings: display: mediatek: control dpi pins mode to avoid leakage 2020-06-22 09:05:13 +02:00
drivers PCI: aardvark: Don't blindly enable ASPM L0s and don't write to read-only register 2020-06-25 15:32:49 +02:00
firmware Fix built-in early-load Intel microcode alignment 2020-01-23 08:21:29 +01:00
fs f2fs: report delalloc reserve as non-free in statfs for project quota 2020-06-25 15:32:49 +02:00
include sunrpc: clean up properly in gss_mech_unregister() 2020-06-22 09:05:29 +02:00
init x86: Fix early boot crash on gcc-10, third try 2020-05-20 08:18:49 +02:00
ipc ipc/util.c: sysvipc_find_ipc() incorrectly updates position index 2020-05-20 08:18:40 +02:00
kernel kernel/cpu_pm: Fix uninitted local in cpu_pm 2020-06-22 09:05:28 +02:00
lib lib/mpi: Fix 64-bit MIPS build with Clang 2020-06-22 09:05:14 +02:00
LICENSES LICENSES: Remove CC-BY-SA-4.0 license text 2018-10-18 11:28:50 +02:00
mm mm: initialize deferred pages with interrupts enabled 2020-06-22 09:05:21 +02:00
net sunrpc: clean up properly in gss_mech_unregister() 2020-06-22 09:05:29 +02:00
samples samples: bpf: Fix build error 2020-06-03 08:19:31 +02:00
scripts gcc-common.h: Update for GCC 10 2020-05-27 17:37:30 +02:00
security ima: Call ima_calc_boot_aggregate() in ima_eventdigest_init() 2020-06-22 09:05:26 +02:00
sound ALSA: isa/wavefront: prevent out of bounds write in ioctl 2020-06-25 15:32:48 +02:00
tools perf symbols: Fix debuginfo search for Ubuntu 2020-06-22 09:05:30 +02:00
usr initramfs: restore default compression behavior 2020-04-13 10:44:59 +02:00
virt KVM: arm64: Synchronize sysreg state on injecting an AArch32 exception 2020-06-22 09:05:09 +02:00
.clang-format clang-format: Set IndentWrappedFunctionNames false 2018-08-01 18:38:51 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap libnvdimm-for-4.19_misc 2018-08-25 18:13:10 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS 9p: remove Ron Minnich from MAINTAINERS 2018-08-17 16:20:26 -07:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS MAINTAINERS: Update drm/i915 bug filing URL 2020-02-28 16:38:49 +01:00
Makefile Linux 4.19.129 2020-06-22 09:05:30 +02:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -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.
See Documentation/00-INDEX for a list of what is contained in each file.

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.