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Liguang Zhang 920facf233 PCI: pciehp: Clear cmd_busy bit in polling mode
commit 92912b1751 upstream.

Writes to a Downstream Port's Slot Control register are PCIe hotplug
"commands."  If the Port supports Command Completed events, software must
wait for a command to complete before writing to Slot Control again.

pcie_do_write_cmd() sets ctrl->cmd_busy when it writes to Slot Control.  If
software notification is enabled, i.e., PCI_EXP_SLTCTL_HPIE and
PCI_EXP_SLTCTL_CCIE are set, ctrl->cmd_busy is cleared by pciehp_isr().

But when software notification is disabled, as it is when pcie_init()
powers off an empty slot, pcie_wait_cmd() uses pcie_poll_cmd() to poll for
command completion, and it neglects to clear ctrl->cmd_busy, which leads to
spurious timeouts:

  pcieport 0000:00:03.0: pciehp: Timeout on hotplug command 0x01c0 (issued 2264 msec ago)
  pcieport 0000:00:03.0: pciehp: Timeout on hotplug command 0x05c0 (issued 2288 msec ago)

Clear ctrl->cmd_busy in pcie_poll_cmd() when it detects a Command Completed
event (PCI_EXP_SLTSTA_CC).

[bhelgaas: commit log]
Fixes: a5dd4b4b05 ("PCI: pciehp: Wait for hotplug command completion where necessary")
Link: https://lore.kernel.org/r/20211111054258.7309-1-zhangliguang@linux.alibaba.com
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215143
Link: https://lore.kernel.org/r/20211126173309.GA12255@wunner.de
Signed-off-by: Liguang Zhang <zhangliguang@linux.alibaba.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
Cc: stable@vger.kernel.org	# v4.19+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-04-08 14:23:04 +02:00
arch xtensa: fix xtensa_wsr always writing 0 2022-04-08 14:23:03 +02:00
block block: don't merge across cgroup boundaries if blkcg is enabled 2022-04-08 14:22:59 +02:00
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Documentation Documentation: update stable tree link 2022-04-08 14:22:51 +02:00
drivers PCI: pciehp: Clear cmd_busy bit in polling mode 2022-04-08 14:23:04 +02:00
fs btrfs: verify the tranisd of the to-be-written dirty extent buffer 2022-04-08 14:23:02 +02:00
include pstore: Don't use semaphores in always-atomic-context code 2022-04-08 14:23:01 +02:00
init init: make unknown command line param message clearer 2021-11-18 19:17:11 +01:00
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samples samples/landlock: Fix path_list memory leak 2022-04-08 14:22:59 +02:00
scripts kconfig: fix failing to generate auto.conf 2022-02-23 12:03:20 +01:00
security landlock: Use square brackets around "landlock-ruleset" 2022-04-08 14:22:59 +02:00
sound ASoC: SOF: Intel: Fix NULL ptr dereference when ENOMEM 2022-04-08 14:22:58 +02:00
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usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2022-02-01 17:27:15 +01:00
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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.