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NUMA systems with ACPI normally describe the physical topology via _PXM methods. But many BIOSes don't implement _PXM, which leaves the kernel with no way to discover the device topology, which reduces performance because we can't put memory and processes close to the device. The NUMA node of a PCI device is already exported in the sysfs "numa_node" file. Make that file writable so users can workaround the lack of _PXM methods in the BIOS. For example: echo 3 > /sys/devices/pci0000:ff/0000:03:1f.3/numa_node sets the node for PCI device 0000:03:1f.3. Writing the file emits a FW_BUG warning to encourage users to request firmware updates. It also taints the kernel with TAINT_FIRMWARE_WORKAROUND because overriding the node incorrectly can cause performance issues. [bhelgaas: changelog, documentation text] Signed-off-by: Prarit Bhargava <prarit@redhat.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> CC: Myron Stowe <mstowe@redhat.com> CC: Alexander Ducyk <alexander.h.duyck@redhat.com> CC: Jiang Liu <jiang.liu@linux.intel.com>
297 lines
12 KiB
Plaintext
297 lines
12 KiB
Plaintext
What: /sys/bus/pci/drivers/.../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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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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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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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/.../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
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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 malformatted data. If the
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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/.../virtfnN
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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/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
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given instance (SMBIOS type 41 device type instance) of the
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PCI device. The attribute will be created only if the firmware
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has given an instance number to the PCI device.
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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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