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Filename Latest commit message Latest commit date
Rongguang Wei 331dce61c0 PCI: pciehp: Cancel bringup sequence if card is not present
[ Upstream commit e8afd0d9fccc27c8ad263db5cf5952cfcf72d6fe ]

If a PCIe hotplug slot has an Attention Button, the normal hot-add flow is:

  - Slot is empty and slot power is off
  - User inserts card in slot and presses Attention Button
  - OS blinks Power Indicator for 5 seconds
  - After 5 seconds, OS turns on Power Indicator, turns on slot power, and
    enumerates the device

Previously, if a user pressed the Attention Button on an *empty* slot,
pciehp logged the following messages and blinked the Power Indicator
until a second button press:

  [0.000] pciehp: Button press: will power on in 5 sec
  [0.001] # Power Indicator starts blinking
  [5.001] # 5 second timeout; slot is empty, so we should cancel the
            request to power on and turn off Power Indicator

  [7.000] # Power Indicator still blinking
  [8.000] # possible card insertion
  [9.000] pciehp: Button press: canceling request to power on

The first button press incorrectly left the slot in BLINKINGON_STATE, so
the second was interpreted as a "cancel power on" event regardless of
whether a card was present.

If the slot is empty, turn off the Power Indicator and return from
BLINKINGON_STATE to OFF_STATE after 5 seconds, effectively canceling the
request to power on.  Putting the slot in OFF_STATE also means the second
button press will correctly request a slot power on if the slot is
occupied.

[bhelgaas: commit log]
Link: https://lore.kernel.org/r/20230512021518.336460-1-clementwei90@163.com
Fixes: d331710ea7 ("PCI: pciehp: Become resilient to missed events")
Suggested-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Rongguang Wei <weirongguang@kylinos.cn>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-07-27 08:37:16 +02:00
arch arm64: dts: renesas: ulcb-kf: Remove flow control for SCIF1 2023-07-27 08:37:14 +02:00
block
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Documentation
drivers PCI: pciehp: Cancel bringup sequence if card is not present 2023-07-27 08:37:16 +02:00
fs
include netlink: Add __sock_i_ino() for __netlink_diag_dump(). 2023-07-27 08:37:12 +02:00
init
ipc
kernel kexec: fix a memory leak in crash_shrink_memory() 2023-07-27 08:37:10 +02:00
lib lib/ts_bm: reset initial match offset for every block of text 2023-07-27 08:37:12 +02:00
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net netlink: Add __sock_i_ino() for __netlink_diag_dump(). 2023-07-27 08:37:12 +02:00
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sound ASoC: imx-audmix: check return value of devm_kasprintf() 2023-07-27 08:37:15 +02:00
tools selftests: rtnetlink: remove netdevsim device after ipsec offload test 2023-07-27 08:37:11 +02:00
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Linux kernel
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There are various text files in the Documentation/ subdirectory,
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Please read the Documentation/process/changes.rst file, as it contains the
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