Documentation/ABI/testing/sysfs-bus-pci

   1 What:           /sys/bus/pci/drivers/.../bind
   2 Date:           December 2003
   3 Contact:        linux-pci@vger.kernel.org
   4 Description:
   5                 Writing a device location to this file will cause
   6                 the driver to attempt to bind to the device found at
   7                 this location.  This is useful for overriding default
   8                 bindings.  The format for the location is: DDDD:BB:DD.F.
   9                 That is Domain:Bus:Device.Function and is the same as
  10                 found in /sys/bus/pci/devices/.  For example:
  11                 # echo 0000:00:19.0 > /sys/bus/pci/drivers/foo/bind
  12                 (Note: kernels before 2.6.28 may require echo -n).
  13
  14 What:           /sys/bus/pci/drivers/.../unbind
  15 Date:           December 2003
  16 Contact:        linux-pci@vger.kernel.org
  17 Description:
  18                 Writing a device location to this file will cause the
  19                 driver to attempt to unbind from the device found at
  20                 this location.  This may be useful when overriding default
  21                 bindings.  The format for the location is: DDDD:BB:DD.F.
  22                 That is Domain:Bus:Device.Function and is the same as
  23                 found in /sys/bus/pci/devices/. For example:
  24                 # echo 0000:00:19.0 > /sys/bus/pci/drivers/foo/unbind
  25                 (Note: kernels before 2.6.28 may require echo -n).
  26
  27 What:           /sys/bus/pci/drivers/.../new_id
  28 Date:           December 2003
  29 Contact:        linux-pci@vger.kernel.org
  30 Description:
  31                 Writing a device ID to this file will attempt to
  32                 dynamically add a new device ID to a PCI device driver.
  33                 This may allow the driver to support more hardware than
  34                 was included in the driver's static device ID support
  35                 table at compile time.  The format for the device ID is:
  36                 VVVV DDDD SVVV SDDD CCCC MMMM PPPP.  That is Vendor ID,
  37                 Device ID, Subsystem Vendor ID, Subsystem Device ID,
  38                 Class, Class Mask, and Private Driver Data.  The Vendor ID
  39                 and Device ID fields are required, the rest are optional.
  40                 Upon successfully adding an ID, the driver will probe
  41                 for the device and attempt to bind to it.  For example:
  42                 # echo "8086 10f5" > /sys/bus/pci/drivers/foo/new_id
  43
  44 What:           /sys/bus/pci/drivers/.../remove_id
  45 Date:           February 2009
  46 Contact:        Chris Wright <chrisw@sous-sol.org>
  47 Description:
  48                 Writing a device ID to this file will remove an ID
  49                 that was dynamically added via the new_id sysfs entry.
  50                 The format for the device ID is:
  51                 VVVV DDDD SVVV SDDD CCCC MMMM.  That is Vendor ID, Device
  52                 ID, Subsystem Vendor ID, Subsystem Device ID, Class,
  53                 and Class Mask.  The Vendor ID and Device ID fields are
  54                 required, the rest are optional.  After successfully
  55                 removing an ID, the driver will no longer support the
  56                 device.  This is useful to ensure auto probing won't
  57                 match the driver to the device.  For example:
  58                 # echo "8086 10f5" > /sys/bus/pci/drivers/foo/remove_id
  59
  60 What:           /sys/bus/pci/rescan
  61 Date:           January 2009
  62 Contact:        Linux PCI developers <linux-pci@vger.kernel.org>
  63 Description:
  64                 Writing a non-zero value to this attribute will
  65                 force a rescan of all PCI buses in the system, and
  66                 re-discover previously removed devices.
  67
  68 What:           /sys/bus/pci/devices/.../msi_irqs/
  69 Date:           September, 2011
  70 Contact:        Neil Horman <nhorman@tuxdriver.com>
  71 Description:
  72                 The /sys/devices/.../msi_irqs directory contains a variable set
  73                 of sub-directories, with each sub-directory being named after a
  74                 corresponding msi irq vector allocated to that device.  Each
  75                 numbered sub-directory N contains attributes of that irq.
  76                 Note that this directory is not created for device drivers which
  77                 do not support msi irqs
  78
  79 What:           /sys/bus/pci/devices/.../msi_irqs/<N>/mode
  80 Date:           September 2011
  81 Contact:        Neil Horman <nhorman@tuxdriver.com>
  82 Description:
  83                 This attribute indicates the mode that the irq vector named by
  84                 the parent directory is in (msi vs. msix)
  85
  86 What:           /sys/bus/pci/devices/.../remove
  87 Date:           January 2009
  88 Contact:        Linux PCI developers <linux-pci@vger.kernel.org>
  89 Description:
  90                 Writing a non-zero value to this attribute will
  91                 hot-remove the PCI device and any of its children.
  92
  93 What:           /sys/bus/pci/devices/.../pci_bus/.../rescan
  94 Date:           May 2011
  95 Contact:        Linux PCI developers <linux-pci@vger.kernel.org>
  96 Description:
  97                 Writing a non-zero value to this attribute will
  98                 force a rescan of the bus and all child buses,
  99                 and re-discover devices removed earlier from this
 100                 part of the device tree.
 101
 102 What:           /sys/bus/pci/devices/.../rescan
 103 Date:           January 2009
 104 Contact:        Linux PCI developers <linux-pci@vger.kernel.org>
 105 Description:
 106                 Writing a non-zero value to this attribute will
 107                 force a rescan of the device's parent bus and all
 108                 child buses, and re-discover devices removed earlier
 109                 from this part of the device tree.
 110
 111 What:           /sys/bus/pci/devices/.../reset
 112 Date:           July 2009
 113 Contact:        Michael S. Tsirkin <mst@redhat.com>
 114 Description:
 115                 Some devices allow an individual function to be reset
 116                 without affecting other functions in the same device.
 117                 For devices that have this support, a file named reset
 118                 will be present in sysfs.  Writing 1 to this file
 119                 will perform reset.
 120
 121 What:           /sys/bus/pci/devices/.../vpd
 122 Date:           February 2008
 123 Contact:        Ben Hutchings <bhutchings@solarflare.com>
 124 Description:
 125                 A file named vpd in a device directory will be a
 126                 binary file containing the Vital Product Data for the
 127                 device.  It should follow the VPD format defined in
 128                 PCI Specification 2.1 or 2.2, but users should consider
 129                 that some devices may have malformatted data.  If the
 130                 underlying VPD has a writable section then the
 131                 corresponding section of this file will be writable.
 132
 133 What:           /sys/bus/pci/devices/.../virtfnN
 134 Date:           March 2009
 135 Contact:        Yu Zhao <yu.zhao@intel.com>
 136 Description:
 137                 This symbolic link appears when hardware supports the SR-IOV
 138                 capability and the Physical Function driver has enabled it.
 139                 The symbolic link points to the PCI device sysfs entry of the
 140                 Virtual Function whose index is N (0...MaxVFs-1).
 141
 142 What:           /sys/bus/pci/devices/.../dep_link
 143 Date:           March 2009
 144 Contact:        Yu Zhao <yu.zhao@intel.com>
 145 Description:
 146                 This symbolic link appears when hardware supports the SR-IOV
 147                 capability and the Physical Function driver has enabled it,
 148                 and this device has vendor specific dependencies with others.
 149                 The symbolic link points to the PCI device sysfs entry of
 150                 Physical Function this device depends on.
 151
 152 What:           /sys/bus/pci/devices/.../physfn
 153 Date:           March 2009
 154 Contact:        Yu Zhao <yu.zhao@intel.com>
 155 Description:
 156                 This symbolic link appears when a device is a Virtual Function.
 157                 The symbolic link points to the PCI device sysfs entry of the
 158                 Physical Function this device associates with.
 159
 160 What:           /sys/bus/pci/slots/.../module
 161 Date:           June 2009
 162 Contact:        linux-pci@vger.kernel.org
 163 Description:
 164                 This symbolic link points to the PCI hotplug controller driver
 165                 module that manages the hotplug slot.
 166
 167 What:           /sys/bus/pci/devices/.../label
 168 Date:           July 2010
 169 Contact:        Narendra K <narendra_k@dell.com>, linux-bugs@dell.com
 170 Description:
 171                 Reading this attribute will provide the firmware
 172                 given name (SMBIOS type 41 string or ACPI _DSM string) of
 173                 the PCI device. The attribute will be created only
 174                 if the firmware has given a name to the PCI device.
 175                 ACPI _DSM string name will be given priority if the
 176                 system firmware provides SMBIOS type 41 string also.
 177 Users:
 178                 Userspace applications interested in knowing the
 179                 firmware assigned name of the PCI device.
 180
 181 What:           /sys/bus/pci/devices/.../index
 182 Date:           July 2010
 183 Contact:        Narendra K <narendra_k@dell.com>, linux-bugs@dell.com
 184 Description:
 185                 Reading this attribute will provide the firmware
 186                 given instance (SMBIOS type 41 device type instance) of the
 187                 PCI device. The attribute will be created only if the firmware
 188                 has given an instance number to the PCI device.
 189 Users:
 190                 Userspace applications interested in knowing the
 191                 firmware assigned device type instance of the PCI
 192                 device that can help in understanding the firmware
 193                 intended order of the PCI device.
 194
 195 What:           /sys/bus/pci/devices/.../acpi_index
 196 Date:           July 2010
 197 Contact:        Narendra K <narendra_k@dell.com>, linux-bugs@dell.com
 198 Description:
 199                 Reading this attribute will provide the firmware
 200                 given instance (ACPI _DSM instance number) of the PCI device.
 201                 The attribute will be created only if the firmware has given
 202                 an instance number to the PCI device. ACPI _DSM instance number
 203                 will be given priority if the system firmware provides SMBIOS
 204                 type 41 device type instance also.
 205 Users:
 206                 Userspace applications interested in knowing the
 207                 firmware assigned instance number of the PCI
 208                 device that can help in understanding the firmware
 209                 intended order of the PCI device.
 210
 211 What:           /sys/bus/pci/devices/.../d3cold_allowed
 212 Date:           July 2012
 213 Contact:        Huang Ying <ying.huang@intel.com>
 214 Description:
 215                 d3cold_allowed is bit to control whether the corresponding PCI
 216                 device can be put into D3Cold state.  If it is cleared, the
 217                 device will never be put into D3Cold state.  If it is set, the
 218                 device may be put into D3Cold state if other requirements are
 219                 satisfied too.  Reading this attribute will show the current
 220                 value of d3cold_allowed bit.  Writing this attribute will set
 221                 the value of d3cold_allowed bit.
 222
 223 What:           /sys/bus/pci/devices/.../sriov_totalvfs
 224 Date:           November 2012
 225 Contact:        Donald Dutile <ddutile@redhat.com>
 226 Description:
 227                 This file appears when a physical PCIe device supports SR-IOV.
 228                 Userspace applications can read this file to determine the
 229                 maximum number of Virtual Functions (VFs) a PCIe physical
 230                 function (PF) can support. Typically, this is the value reported
 231                 in the PF's SR-IOV extended capability structure's TotalVFs
 232                 element.  Drivers have the ability at probe time to reduce the
 233                 value read from this file via the pci_sriov_set_totalvfs()
 234                 function.
 235
 236 What:           /sys/bus/pci/devices/.../sriov_numvfs
 237 Date:           November 2012
 238 Contact:        Donald Dutile <ddutile@redhat.com>
 239 Description:
 240                 This file appears when a physical PCIe device supports SR-IOV.
 241                 Userspace applications can read and write to this file to
 242                 determine and control the enablement or disablement of Virtual
 243                 Functions (VFs) on the physical function (PF). A read of this
 244                 file will return the number of VFs that are enabled on this PF.
 245                 A number written to this file will enable the specified
 246                 number of VFs. A userspace application would typically read the
 247                 file and check that the value is zero, and then write the number
 248                 of VFs that should be enabled on the PF; the value written
 249                 should be less than or equal to the value in the sriov_totalvfs
 250                 file. A userspace application wanting to disable the VFs would
 251                 write a zero to this file. The core ensures that valid values
 252                 are written to this file, and returns errors when values are not
 253                 valid.  For example, writing a 2 to this file when sriov_numvfs
 254                 is not 0 and not 2 already will return an error. Writing a 10
 255                 when the value of sriov_totalvfs is 8 will return an error.