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6d4338cb40
Add documentation for the p2pmem/allocate binary file which allows for allocating p2pmem buffers in userspace for passing to drivers that support them. (Currently only O_DIRECT to NVMe devices.) Signed-off-by: Logan Gunthorpe <logang@deltatee.com> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Link: https://lore.kernel.org/r/20221021174116.7200-10-logang@deltatee.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
503 lines
20 KiB
Plaintext
503 lines
20 KiB
Plaintext
What: /sys/bus/pci/drivers/.../bind
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What: /sys/devices/pciX/.../bind
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Date: December 2003
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Contact: linux-pci@vger.kernel.org
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Description:
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Writing a device location to this file will cause
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the driver to attempt to bind to the device found at
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this location. This is useful for overriding default
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bindings. The format for the location is: DDDD:BB:DD.F.
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That is Domain:Bus:Device.Function and is the same as
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found in /sys/bus/pci/devices/. For example::
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# echo 0000:00:19.0 > /sys/bus/pci/drivers/foo/bind
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(Note: kernels before 2.6.28 may require echo -n).
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What: /sys/bus/pci/drivers/.../unbind
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What: /sys/devices/pciX/.../unbind
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Date: December 2003
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Contact: linux-pci@vger.kernel.org
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Description:
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Writing a device location to this file will cause the
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driver to attempt to unbind from the device found at
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this location. This may be useful when overriding default
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bindings. The format for the location is: DDDD:BB:DD.F.
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That is Domain:Bus:Device.Function and is the same as
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found in /sys/bus/pci/devices/. For example::
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# echo 0000:00:19.0 > /sys/bus/pci/drivers/foo/unbind
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(Note: kernels before 2.6.28 may require echo -n).
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What: /sys/bus/pci/drivers/.../new_id
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What: /sys/devices/pciX/.../new_id
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Date: December 2003
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Contact: linux-pci@vger.kernel.org
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Description:
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Writing a device ID to this file will attempt to
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dynamically add a new device ID to a PCI device driver.
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This may allow the driver to support more hardware than
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was included in the driver's static device ID support
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table at compile time. The format for the device ID is:
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VVVV DDDD SVVV SDDD CCCC MMMM PPPP. That is Vendor ID,
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Device ID, Subsystem Vendor ID, Subsystem Device ID,
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Class, Class Mask, and Private Driver Data. The Vendor ID
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and Device ID fields are required, the rest are optional.
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Upon successfully adding an ID, the driver will probe
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for the device and attempt to bind to it. For example::
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# echo "8086 10f5" > /sys/bus/pci/drivers/foo/new_id
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What: /sys/bus/pci/drivers/.../remove_id
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What: /sys/devices/pciX/.../remove_id
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Date: February 2009
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Contact: Chris Wright <chrisw@sous-sol.org>
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Description:
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Writing a device ID to this file will remove an ID
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that was dynamically added via the new_id sysfs entry.
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The format for the device ID is:
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VVVV DDDD SVVV SDDD CCCC MMMM. That is Vendor ID, Device
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ID, Subsystem Vendor ID, Subsystem Device ID, Class,
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and Class Mask. The Vendor ID and Device ID fields are
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required, the rest are optional. After successfully
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removing an ID, the driver will no longer support the
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device. This is useful to ensure auto probing won't
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match the driver to the device. For example::
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# echo "8086 10f5" > /sys/bus/pci/drivers/foo/remove_id
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What: /sys/bus/pci/rescan
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Date: January 2009
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Contact: Linux PCI developers <linux-pci@vger.kernel.org>
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Description:
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Writing a non-zero value to this attribute will
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force a rescan of all PCI buses in the system, and
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re-discover previously removed devices.
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What: /sys/bus/pci/devices/.../msi_bus
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Date: September 2014
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Contact: Linux PCI developers <linux-pci@vger.kernel.org>
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Description:
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Writing a zero value to this attribute disallows MSI and
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MSI-X for any future drivers of the device. If the device
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is a bridge, MSI and MSI-X will be disallowed for future
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drivers of all child devices under the bridge. Drivers
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must be reloaded for the new setting to take effect.
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What: /sys/bus/pci/devices/.../msi_irqs/
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Date: September, 2011
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Contact: Neil Horman <nhorman@tuxdriver.com>
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Description:
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The /sys/devices/.../msi_irqs directory contains a variable set
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of files, with each file being named after a corresponding msi
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irq vector allocated to that device.
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What: /sys/bus/pci/devices/.../msi_irqs/<N>
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Date: September 2011
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Contact: Neil Horman <nhorman@tuxdriver.com>
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Description:
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This attribute indicates the mode that the irq vector named by
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the file is in (msi vs. msix)
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What: /sys/bus/pci/devices/.../irq
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Date: August 2021
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Contact: Linux PCI developers <linux-pci@vger.kernel.org>
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Description:
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If a driver has enabled MSI (not MSI-X), "irq" contains the
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IRQ of the first MSI vector. Otherwise "irq" contains the
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IRQ of the legacy INTx interrupt.
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"irq" being set to 0 indicates that the device isn't
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capable of generating legacy INTx interrupts.
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What: /sys/bus/pci/devices/.../remove
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Date: January 2009
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Contact: Linux PCI developers <linux-pci@vger.kernel.org>
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Description:
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Writing a non-zero value to this attribute will
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hot-remove the PCI device and any of its children.
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What: /sys/bus/pci/devices/.../pci_bus/.../rescan
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Date: May 2011
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Contact: Linux PCI developers <linux-pci@vger.kernel.org>
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Description:
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Writing a non-zero value to this attribute will
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force a rescan of the bus and all child buses,
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and re-discover devices removed earlier from this
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part of the device tree.
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What: /sys/bus/pci/devices/.../rescan
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Date: January 2009
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Contact: Linux PCI developers <linux-pci@vger.kernel.org>
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Description:
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Writing a non-zero value to this attribute will
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force a rescan of the device's parent bus and all
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child buses, and re-discover devices removed earlier
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from this part of the device tree.
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What: /sys/bus/pci/devices/.../reset_method
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Date: August 2021
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Contact: Amey Narkhede <ameynarkhede03@gmail.com>
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Description:
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Some devices allow an individual function to be reset
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without affecting other functions in the same slot.
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For devices that have this support, a file named
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reset_method is present in sysfs. Reading this file
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gives names of the supported and enabled reset methods and
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their ordering. Writing a space-separated list of names of
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reset methods sets the reset methods and ordering to be
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used when resetting the device. Writing an empty string
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disables the ability to reset the device. Writing
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"default" enables all supported reset methods in the
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default ordering.
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What: /sys/bus/pci/devices/.../reset
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Date: July 2009
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Contact: Michael S. Tsirkin <mst@redhat.com>
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Description:
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Some devices allow an individual function to be reset
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without affecting other functions in the same device.
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For devices that have this support, a file named reset
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will be present in sysfs. Writing 1 to this file
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will perform reset.
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What: /sys/bus/pci/devices/.../vpd
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Date: February 2008
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Contact: Ben Hutchings <bwh@kernel.org>
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Description:
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A file named vpd in a device directory will be a
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binary file containing the Vital Product Data for the
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device. It should follow the VPD format defined in
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PCI Specification 2.1 or 2.2, but users should consider
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that some devices may have incorrectly formatted data.
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If the underlying VPD has a writable section then the
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corresponding section of this file will be writable.
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What: /sys/bus/pci/devices/.../virtfn<N>
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Date: March 2009
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Contact: Yu Zhao <yu.zhao@intel.com>
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Description:
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This symbolic link appears when hardware supports the SR-IOV
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capability and the Physical Function driver has enabled it.
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The symbolic link points to the PCI device sysfs entry of the
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Virtual Function whose index is N (0...MaxVFs-1).
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What: /sys/bus/pci/devices/.../dep_link
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Date: March 2009
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Contact: Yu Zhao <yu.zhao@intel.com>
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Description:
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This symbolic link appears when hardware supports the SR-IOV
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capability and the Physical Function driver has enabled it,
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and this device has vendor specific dependencies with others.
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The symbolic link points to the PCI device sysfs entry of
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Physical Function this device depends on.
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What: /sys/bus/pci/devices/.../physfn
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Date: March 2009
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Contact: Yu Zhao <yu.zhao@intel.com>
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Description:
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This symbolic link appears when a device is a Virtual Function.
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The symbolic link points to the PCI device sysfs entry of the
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Physical Function this device associates with.
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What: /sys/bus/pci/devices/.../modalias
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Date: May 2005
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Contact: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Description:
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This attribute indicates the PCI ID of the device object.
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That is in the format:
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pci:vXXXXXXXXdXXXXXXXXsvXXXXXXXXsdXXXXXXXXbcXXscXXiXX,
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where:
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- vXXXXXXXX contains the vendor ID;
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- dXXXXXXXX contains the device ID;
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- svXXXXXXXX contains the sub-vendor ID;
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- sdXXXXXXXX contains the subsystem device ID;
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- bcXX contains the device class;
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- scXX contains the device subclass;
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- iXX contains the device class programming interface.
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What: /sys/bus/pci/slots/.../module
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Date: June 2009
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Contact: linux-pci@vger.kernel.org
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Description:
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This symbolic link points to the PCI hotplug controller driver
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module that manages the hotplug slot.
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What: /sys/bus/pci/devices/.../label
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Date: July 2010
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Contact: Narendra K <narendra_k@dell.com>, linux-bugs@dell.com
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Description:
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Reading this attribute will provide the firmware
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given name (SMBIOS type 41 string or ACPI _DSM string) of
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the PCI device. The attribute will be created only
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if the firmware has given a name to the PCI device.
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ACPI _DSM string name will be given priority if the
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system firmware provides SMBIOS type 41 string also.
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Users:
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Userspace applications interested in knowing the
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firmware assigned name of the PCI device.
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What: /sys/bus/pci/devices/.../index
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Date: July 2010
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Contact: Narendra K <narendra_k@dell.com>, linux-bugs@dell.com
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Description:
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Reading this attribute will provide the firmware given instance
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number of the PCI device. Depending on the platform this can
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be for example the SMBIOS type 41 device type instance or the
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user-defined ID (UID) on s390. The attribute will be created
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only if the firmware has given an instance number to the PCI
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device and that number is guaranteed to uniquely identify the
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device in the system.
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Users:
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Userspace applications interested in knowing the
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firmware assigned device type instance of the PCI
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device that can help in understanding the firmware
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intended order of the PCI device.
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What: /sys/bus/pci/devices/.../acpi_index
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Date: July 2010
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Contact: Narendra K <narendra_k@dell.com>, linux-bugs@dell.com
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Description:
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Reading this attribute will provide the firmware
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given instance (ACPI _DSM instance number) of the PCI device.
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The attribute will be created only if the firmware has given
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an instance number to the PCI device. ACPI _DSM instance number
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will be given priority if the system firmware provides SMBIOS
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type 41 device type instance also.
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Users:
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Userspace applications interested in knowing the
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firmware assigned instance number of the PCI
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device that can help in understanding the firmware
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intended order of the PCI device.
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What: /sys/bus/pci/devices/.../d3cold_allowed
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Date: July 2012
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Contact: Huang Ying <ying.huang@intel.com>
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Description:
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d3cold_allowed is bit to control whether the corresponding PCI
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device can be put into D3Cold state. If it is cleared, the
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device will never be put into D3Cold state. If it is set, the
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device may be put into D3Cold state if other requirements are
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satisfied too. Reading this attribute will show the current
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value of d3cold_allowed bit. Writing this attribute will set
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the value of d3cold_allowed bit.
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What: /sys/bus/pci/devices/.../sriov_totalvfs
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Date: November 2012
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Contact: Donald Dutile <ddutile@redhat.com>
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Description:
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This file appears when a physical PCIe device supports SR-IOV.
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Userspace applications can read this file to determine the
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maximum number of Virtual Functions (VFs) a PCIe physical
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function (PF) can support. Typically, this is the value reported
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in the PF's SR-IOV extended capability structure's TotalVFs
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element. Drivers have the ability at probe time to reduce the
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value read from this file via the pci_sriov_set_totalvfs()
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function.
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What: /sys/bus/pci/devices/.../sriov_numvfs
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Date: November 2012
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Contact: Donald Dutile <ddutile@redhat.com>
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Description:
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This file appears when a physical PCIe device supports SR-IOV.
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Userspace applications can read and write to this file to
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determine and control the enablement or disablement of Virtual
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Functions (VFs) on the physical function (PF). A read of this
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file will return the number of VFs that are enabled on this PF.
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A number written to this file will enable the specified
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number of VFs. A userspace application would typically read the
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file and check that the value is zero, and then write the number
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of VFs that should be enabled on the PF; the value written
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should be less than or equal to the value in the sriov_totalvfs
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file. A userspace application wanting to disable the VFs would
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write a zero to this file. The core ensures that valid values
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are written to this file, and returns errors when values are not
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valid. For example, writing a 2 to this file when sriov_numvfs
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is not 0 and not 2 already will return an error. Writing a 10
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when the value of sriov_totalvfs is 8 will return an error.
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What: /sys/bus/pci/devices/.../driver_override
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Date: April 2014
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Contact: Alex Williamson <alex.williamson@redhat.com>
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Description:
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This file allows the driver for a device to be specified which
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will override standard static and dynamic ID matching. When
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specified, only a driver with a name matching the value written
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to driver_override will have an opportunity to bind to the
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device. The override is specified by writing a string to the
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driver_override file (echo pci-stub > driver_override) and
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may be cleared with an empty string (echo > driver_override).
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This returns the device to standard matching rules binding.
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Writing to driver_override does not automatically unbind the
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device from its current driver or make any attempt to
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automatically load the specified driver. If no driver with a
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matching name is currently loaded in the kernel, the device
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will not bind to any driver. This also allows devices to
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opt-out of driver binding using a driver_override name such as
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"none". Only a single driver may be specified in the override,
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there is no support for parsing delimiters.
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What: /sys/bus/pci/devices/.../numa_node
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Date: Oct 2014
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Contact: Prarit Bhargava <prarit@redhat.com>
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Description:
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This file contains the NUMA node to which the PCI device is
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attached, or -1 if the node is unknown. The initial value
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comes from an ACPI _PXM method or a similar firmware
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source. If that is missing or incorrect, this file can be
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written to override the node. In that case, please report
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a firmware bug to the system vendor. Writing to this file
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taints the kernel with TAINT_FIRMWARE_WORKAROUND, which
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reduces the supportability of your system.
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What: /sys/bus/pci/devices/.../revision
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Date: November 2016
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Contact: Emil Velikov <emil.l.velikov@gmail.com>
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Description:
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This file contains the revision field of the PCI device.
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The value comes from device config space. The file is read only.
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What: /sys/bus/pci/devices/.../sriov_drivers_autoprobe
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Date: April 2017
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Contact: Bodong Wang<bodong@mellanox.com>
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Description:
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This file is associated with the PF of a device that
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supports SR-IOV. It determines whether newly-enabled VFs
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are immediately bound to a driver. It initially contains
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1, which means the kernel automatically binds VFs to a
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compatible driver immediately after they are enabled. If
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an application writes 0 to the file before enabling VFs,
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the kernel will not bind VFs to a driver.
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A typical use case is to write 0 to this file, then enable
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VFs, then assign the newly-created VFs to virtual machines.
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Note that changing this file does not affect already-
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enabled VFs. In this scenario, the user must first disable
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the VFs, write 0 to sriov_drivers_autoprobe, then re-enable
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the VFs.
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This is similar to /sys/bus/pci/drivers_autoprobe, but
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affects only the VFs associated with a specific PF.
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What: /sys/bus/pci/devices/.../p2pmem/size
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Date: November 2017
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Contact: Logan Gunthorpe <logang@deltatee.com>
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Description:
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If the device has any Peer-to-Peer memory registered, this
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file contains the total amount of memory that the device
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provides (in decimal).
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What: /sys/bus/pci/devices/.../p2pmem/available
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Date: November 2017
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Contact: Logan Gunthorpe <logang@deltatee.com>
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Description:
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If the device has any Peer-to-Peer memory registered, this
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file contains the amount of memory that has not been
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allocated (in decimal).
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What: /sys/bus/pci/devices/.../p2pmem/published
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Date: November 2017
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Contact: Logan Gunthorpe <logang@deltatee.com>
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Description:
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If the device has any Peer-to-Peer memory registered, this
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file contains a '1' if the memory has been published for
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use outside the driver that owns the device.
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What: /sys/bus/pci/devices/.../p2pmem/allocate
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Date: August 2022
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Contact: Logan Gunthorpe <logang@deltatee.com>
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Description:
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This file allows mapping p2pmem into userspace. For each
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mmap() call on this file, the kernel will allocate a chunk
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of Peer-to-Peer memory for use in Peer-to-Peer transactions.
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This memory can be used in O_DIRECT calls to NVMe backed
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files for Peer-to-Peer copies.
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What: /sys/bus/pci/devices/.../link/clkpm
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/sys/bus/pci/devices/.../link/l0s_aspm
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/sys/bus/pci/devices/.../link/l1_aspm
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/sys/bus/pci/devices/.../link/l1_1_aspm
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/sys/bus/pci/devices/.../link/l1_2_aspm
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/sys/bus/pci/devices/.../link/l1_1_pcipm
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/sys/bus/pci/devices/.../link/l1_2_pcipm
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Date: October 2019
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Contact: Heiner Kallweit <hkallweit1@gmail.com>
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Description: If ASPM is supported for an endpoint, these files can be
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used to disable or enable the individual power management
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states. Write y/1/on to enable, n/0/off to disable.
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What: /sys/bus/pci/devices/.../power_state
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Date: November 2020
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Contact: Linux PCI developers <linux-pci@vger.kernel.org>
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Description:
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This file contains the current PCI power state of the device.
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The value comes from the PCI kernel device state and can be one
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of: "unknown", "error", "D0", D1", "D2", "D3hot", "D3cold".
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The file is read only.
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What: /sys/bus/pci/devices/.../sriov_vf_total_msix
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Date: January 2021
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Contact: Leon Romanovsky <leonro@nvidia.com>
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Description:
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This file is associated with a SR-IOV physical function (PF).
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It contains the total number of MSI-X vectors available for
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assignment to all virtual functions (VFs) associated with PF.
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The value will be zero if the device doesn't support this
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functionality. For supported devices, the value will be
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constant and won't be changed after MSI-X vectors assignment.
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What: /sys/bus/pci/devices/.../sriov_vf_msix_count
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Date: January 2021
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Contact: Leon Romanovsky <leonro@nvidia.com>
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Description:
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This file is associated with a SR-IOV virtual function (VF).
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It allows configuration of the number of MSI-X vectors for
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the VF. This allows devices that have a global pool of MSI-X
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vectors to optimally divide them between VFs based on VF usage.
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The values accepted are:
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* > 0 - this number will be reported as the Table Size in the
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VF's MSI-X capability
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* < 0 - not valid
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* = 0 - will reset to the device default value
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The file is writable if the PF is bound to a driver that
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implements ->sriov_set_msix_vec_count().
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What: /sys/bus/pci/devices/.../resourceN_resize
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Date: September 2022
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Contact: Alex Williamson <alex.williamson@redhat.com>
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Description:
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These files provide an interface to PCIe Resizable BAR support.
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A file is created for each BAR resource (N) supported by the
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PCIe Resizable BAR extended capability of the device. Reading
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each file exposes the bitmap of available resource sizes:
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# cat resource1_resize
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00000000000001c0
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The bitmap represents supported resource sizes for the BAR,
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where bit0 = 1MB, bit1 = 2MB, bit2 = 4MB, etc. In the above
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example the device supports 64MB, 128MB, and 256MB BAR sizes.
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When writing the file, the user provides the bit position of
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the desired resource size, for example:
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# echo 7 > resource1_resize
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This indicates to set the size value corresponding to bit 7,
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128MB. The resulting size is 2 ^ (bit# + 20). This definition
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matches the PCIe specification of this capability.
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In order to make use of resource resizing, all PCI drivers must
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be unbound from the device and peer devices under the same
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parent bridge may need to be soft removed. In the case of
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VGA devices, writing a resize value will remove low level
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console drivers from the device. Raw users of pci-sysfs
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resourceN attributes must be terminated prior to resizing.
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Success of the resizing operation is not guaranteed.
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