[ Upstream commit 2fa046449a82a7d0f6d9721dd83e348816038444 ]
The "bus" and "cxl_bus" reset methods reset a device by asserting Secondary
Bus Reset on the bridge leading to the device. These only work if the
device is the only device below the bridge.
Add a sysfs 'reset_subordinate' attribute on bridges that can assert
Secondary Bus Reset regardless of how many devices are below the bridge.
This resets all the devices below a bridge in a single command, including
the locking and config space save/restore that reset methods normally do.
This may be the only way to reset devices that don't support other reset
methods (ACPI, FLR, PM reset, etc).
Link: https://lore.kernel.org/r/20241025222755.3756162-1-kbusch@meta.com
Signed-off-by: Keith Busch <kbusch@kernel.org>
[bhelgaas: commit log, add capable(CAP_SYS_ADMIN) check]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Amey Narkhede <ameynarkhede03@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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>
