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Wei Fang b3608fe28f net: fec: Set mac_managed_pm during probe 
[ Upstream commit cbc17e7802 ]

Setting mac_managed_pm during interface up is too late.

In situations where the link is not brought up yet and the system suspends
the regular PHY power management will run. Since the FEC ETHEREN control
bit is cleared (automatically) on suspend the controller is off in resume.
When the regular PHY power management resume path runs in this context it
will write to the MII_DATA register but nothing will be transmitted on the
MDIO bus.

This can be observed by the following log:

    fec 5b040000.ethernet eth0: MDIO read timeout
    Microchip LAN87xx T1 5b040000.ethernet-1:04: PM: dpm_run_callback(): mdio_bus_phy_resume+0x0/0xc8 returns -110
    Microchip LAN87xx T1 5b040000.ethernet-1:04: PM: failed to resume: error -110

The data written will however remain in the MII_DATA register.

When the link later is set to administrative up it will trigger a call to
fec_restart() which will restore the MII_SPEED register. This triggers the
quirk explained in f166f890c8 ("net: ethernet: fec: Replace interrupt
driven MDIO with polled IO") causing an extra MII_EVENT.

This extra event desynchronizes all the MDIO register reads, causing them
to complete too early. Leading all reads to read as 0 because
fec_enet_mdio_wait() returns too early.

When a Microchip LAN8700R PHY is connected to the FEC, the 0 reads causes
the PHY to be initialized incorrectly and the PHY will not transmit any
ethernet signal in this state. It cannot be brought out of this state
without a power cycle of the PHY.

Fixes: 557d5dc83f ("net: fec: use mac-managed PHY PM")
Closes: https://lore.kernel.org/netdev/1f45bdbe-eab1-4e59-8f24-add177590d27@actia.se/
Signed-off-by: Wei Fang <wei.fang@nxp.com>
[jernberg: commit message]
Signed-off-by: John Ernberg <john.ernberg@actia.se>
Link: https://lore.kernel.org/r/20240328155909.59613-2-john.ernberg@actia.se
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2024-04-10 16:28:29 +02:00
arch x86/retpoline: Do the necessary fixup to the Zen3/4 srso return thunk for !SRSO 2024-04-10 16:28:26 +02:00
block block: Do not force full zone append completion in req_bio_endio() 2024-04-03 15:19:49 +02:00
certs certs: Fix build error when PKCS#11 URI contains semicolon 2023-02-09 11:28:11 +01:00
crypto crypto: jitter - fix CRYPTO_JITTERENTROPY help text 2024-03-26 18:20:50 -04:00
Documentation x86/cpu: Enable STIBP on AMD if Automatic IBRS is enabled 2024-04-03 15:19:54 +02:00
drivers net: fec: Set mac_managed_pm during probe 2024-04-10 16:28:29 +02:00
fs vboxsf: Avoid an spurious warning if load_nls_xxx() fails 2024-04-10 16:28:25 +02:00
include udp: do not accept non-tunnel GSO skbs landing in a tunnel 2024-04-10 16:28:27 +02:00
init init: open /initrd.image with O_LARGEFILE 2024-04-03 15:19:47 +02:00
io_uring io_uring/net: correctly handle multishot recvmsg retry setup 2024-04-03 15:19:33 +02:00
ipc ipc: fix memory leak in init_mqueue_fs() 2022-12-31 13:32:01 +01:00
kernel bpf: Protect against int overflow for stack access size 2024-04-10 16:28:23 +02:00
lib pci_iounmap(): Fix MMIO mapping leak 2024-04-03 15:19:25 +02:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm mm/migrate: set swap entry values of THP tail pages properly. 2024-04-03 15:19:47 +02:00
net tcp: Fix bind() regression for v6-only wildcard and v4(-mapped-v6) non-wildcard addresses. 2024-04-10 16:28:29 +02:00
rust rust: allocator: Prevent mis-aligned allocation 2023-08-11 12:08:18 +02:00
samples work around gcc bugs with 'asm goto' with outputs 2024-02-23 09:12:28 +01:00
scripts scripts/bpf_doc: Use silent mode when exec make cmd 2024-04-10 16:28:21 +02:00
security landlock: Warn once if a Landlock action is requested while disabled 2024-04-03 15:19:32 +02:00
sound ALSA: sh: aica: reorder cleanup operations to avoid UAF bugs 2024-04-03 15:19:50 +02:00
tools selftests: reuseaddr_conflict: add missing new line at the end of the output 2024-04-10 16:28:27 +02:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt KVM: Always flush async #PF workqueue when vCPU is being destroyed 2024-04-03 15:19:25 +02:00
.clang-format inet: ping: use hlist_nulls rcu iterator during lookup 2022-12-01 12:42:46 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore Kbuild: add Rust support 2022-09-28 09:02:20 +02:00
.mailmap 9 hotfixes. 6 for MM, 3 for other areas. Four of these patches address 2022-12-10 17:10:52 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Remove Michal Marek from Kbuild maintainers 2022-11-16 14:53:00 +09:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS trace: Relocate event helper files 2024-03-06 14:45:17 +00:00
Makefile Linux 6.1.84 2024-04-03 15:19:55 +02:00
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.