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Joakim Zhang 276aae3772 net: stmmac: fix system hang caused by eee_ctrl_timer during suspend/resume
commit 5f58591323 ("net: stmmac: delete the eee_ctrl_timer after
napi disabled"), this patch tries to fix system hang caused by eee_ctrl_timer,
unfortunately, it only can resolve it for system reboot stress test. System
hang also can be reproduced easily during system suspend/resume stess test
when mount NFS on i.MX8MP EVK board.

In stmmac driver, eee feature is combined to phylink framework. When do
system suspend, phylink_stop() would queue delayed work, it invokes
stmmac_mac_link_down(), where to deactivate eee_ctrl_timer synchronizly.
In above commit, try to fix issue by deactivating eee_ctrl_timer obviously,
but it is not enough. Looking into eee_ctrl_timer expire callback
stmmac_eee_ctrl_timer(), it could enable hareware eee mode again. What is
unexpected is that LPI interrupt (MAC_Interrupt_Enable.LPIEN bit) is always
asserted. This interrupt has chance to be issued when LPI state entry/exit
from the MAC, and at that time, clock could have been already disabled.
The result is that system hang when driver try to touch register from
interrupt handler.

The reason why above commit can fix system hang issue in stmmac_release()
is that, deactivate eee_ctrl_timer not just after napi disabled, further
after irq freed.

In conclusion, hardware would generate LPI interrupt when clock has been
disabled during suspend or resume, since hardware is in eee mode and LPI
interrupt enabled.

Interrupts from MAC, MTL and DMA level are enabled and never been disabled
when system suspend, so postpone clocks management from suspend stage to
noirq suspend stage should be more safe.

Fixes: 5f58591323 ("net: stmmac: delete the eee_ctrl_timer after napi disabled")
Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-09-08 12:28:26 +01:00
arch ARM: 2021-09-07 13:40:51 -07:00
block block-5.15-2021-09-05 2021-09-06 10:06:26 -07:00
certs certs: Add support for using elliptic curve keys for signing modules 2021-08-23 19:55:42 +03:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2021-08-30 12:57:10 -07:00
Documentation dt-bindings: net: sun8i-emac: Add compatible for D1 2021-09-08 11:27:34 +01:00
drivers net: stmmac: fix system hang caused by eee_ctrl_timer during suspend/resume 2021-09-08 12:28:26 +01:00
fs fuse update for 5.15 2021-09-07 12:18:29 -07:00
include Networking stragglers and fixes for 5.15-rc1, including changes from netfilter, 2021-09-07 14:02:58 -07:00
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kernel kgdb patches for 5.15 2021-09-07 12:08:04 -07:00
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samples kgdb patches for 5.15 2021-09-07 12:08:04 -07:00
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virt KVM: Drop unused kvm_dirty_gfn_invalid() 2021-09-06 08:23:46 -04:00
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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 Networking stragglers and fixes for 5.15-rc1, including changes from netfilter, 2021-09-07 14:02:58 -07:00
Makefile Enable '-Werror' by default for all kernel builds 2021-09-05 11:24:05 -07:00
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.