Mario Limonciello 221952c07b PCI/PM: Skip resuming to D0 if device is disconnected
[ Upstream commit 299fad4133677b845ce962f78c9cf75bded63f61 ]

When a device is surprise-removed (e.g., due to a dock unplug), the PCI
core unconfigures all downstream devices and sets their error state to
pci_channel_io_perm_failure. This marks them as disconnected via
pci_dev_is_disconnected().

During device removal, the runtime PM framework may attempt to resume the
device to D0 via pm_runtime_get_sync(), which calls into pci_power_up().
Since the device is already disconnected, this resume attempt is
unnecessary and results in a predictable errors like this, typically when
undocking from a TBT3 or USB4 dock with PCIe tunneling:

  pci 0000:01:00.0: Unable to change power state from D3cold to D0, device inaccessible

Avoid powering up disconnected devices by checking their status early in
pci_power_up() and returning -EIO.

Suggested-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
[bhelgaas: add typical message]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael@kernel.org>
Link: https://patch.msgid.link/20250909031916.4143121-1-superm1@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-11-24 10:29:42 +01:00
2025-11-24 10:29:40 +01:00
2022-09-28 09:02:20 +02:00
2025-11-02 22:14:42 +09:00

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.
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