0763bcef47
commit 70b70a4307cccebe91388337b1c85735ce4de6ff upstream.
struct pci_dev contains two flags which govern whether the device may
suspend to D3cold:
* no_d3cold provides an opt-out for drivers (e.g. if a device is known
to not wake from D3cold)
* d3cold_allowed provides an opt-out for user space (default is true,
user space may set to false)
Since commit 9d26d3a8f1b0 ("PCI: Put PCIe ports into D3 during suspend"),
the user space setting overwrites the driver setting. Essentially user
space is trusted to know better than the driver whether D3cold is
working.
That feels unsafe and wrong. Assume that the change was introduced
inadvertently and do not overwrite no_d3cold when d3cold_allowed is
modified. Instead, consider d3cold_allowed in addition to no_d3cold
when choosing a suspend state for the device.
That way, user space may opt out of D3cold if the driver hasn't, but it
may no longer force an opt in if the driver has opted out.
Fixes: 9d26d3a8f1b0 ("PCI: Put PCIe ports into D3 during suspend")
Link: https://lore.kernel.org/r/b8a7f4af2b73f6b506ad8ddee59d747cbf834606.1695025365.git.lukas@wunner.de
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Cc: stable@vger.kernel.org # v4.8+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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.