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Commit26112ddc25(PCI / ACPI / PM: Resume bridges w/o drivers on suspend-to-RAM) attempted to fix a functional regression resulting from commitc62ec4610c(PM / core: Fix direct_complete handling for devices with no callbacks) by resuming PCI bridges without drivers (that is, "parallel PCI" ones) during system-wide suspend if the target system state is not ACPI S0 (working state). That turns out insufficient, however, as it is reported that, at least in one case, the platform firmware gets confused if a PCIe root port is suspended before entering the ACPI S3 sleep state. That issue was exposed by commit 77b3729ca03 (PCI / PM: Use SMART_SUSPEND and LEAVE_SUSPENDED flags for PCIe ports) that allowed PCIe ports to stay in runtime suspend during system-wide suspend (which is OK for suspend-to-idle, but turns out to be problematic otherwise). For this reason, drop the driver check from acpi_pci_need_resume() and resume all bridges (including PCIe ports with drivers) during system-wide suspend if the target system state is not ACPI S0. [If the target system state is ACPI S0, it means suspend-to-idle and the platform firmware is not going to be invoked to actually suspend the system, so there is no need to resume the bridges in that case.] Fixes: 77b3729ca03 (PCI / PM: Use SMART_SUSPEND and LEAVE_SUSPENDED flags for PCIe ports) Link: https://bugzilla.kernel.org/show_bug.cgi?id=200675 Reported-by: teika kazura <teika@gmx.com> Tested-by: teika kazura <teika@gmx.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Acked-by: Bjorn Helgaas <bhelgaas@google.com> Cc: 4.16+ <stable@vger.kernel.org> # 4.16+:26112ddc25(PCI / ACPI / PM: Resume bridges ...) Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.