1What: /sys/bus/pci/drivers/.../bind 2What: /sys/devices/pciX/.../bind 3Date: December 2003 4Contact: linux-pci@vger.kernel.org 5Description: 6 Writing a device location to this file will cause 7 the driver to attempt to bind to the device found at 8 this location. This is useful for overriding default 9 bindings. The format for the location is: DDDD:BB:DD.F. 10 That is Domain:Bus:Device.Function and is the same as 11 found in /sys/bus/pci/devices/. For example:: 12 13 # echo 0000:00:19.0 > /sys/bus/pci/drivers/foo/bind 14 15 (Note: kernels before 2.6.28 may require echo -n). 16 17What: /sys/bus/pci/drivers/.../unbind 18What: /sys/devices/pciX/.../unbind 19Date: December 2003 20Contact: linux-pci@vger.kernel.org 21Description: 22 Writing a device location to this file will cause the 23 driver to attempt to unbind from the device found at 24 this location. This may be useful when overriding default 25 bindings. The format for the location is: DDDD:BB:DD.F. 26 That is Domain:Bus:Device.Function and is the same as 27 found in /sys/bus/pci/devices/. For example:: 28 29 # echo 0000:00:19.0 > /sys/bus/pci/drivers/foo/unbind 30 31 (Note: kernels before 2.6.28 may require echo -n). 32 33What: /sys/bus/pci/drivers/.../new_id 34What: /sys/devices/pciX/.../new_id 35Date: December 2003 36Contact: linux-pci@vger.kernel.org 37Description: 38 Writing a device ID to this file will attempt to 39 dynamically add a new device ID to a PCI device driver. 40 This may allow the driver to support more hardware than 41 was included in the driver's static device ID support 42 table at compile time. The format for the device ID is: 43 VVVV DDDD SVVV SDDD CCCC MMMM PPPP. That is Vendor ID, 44 Device ID, Subsystem Vendor ID, Subsystem Device ID, 45 Class, Class Mask, and Private Driver Data. The Vendor ID 46 and Device ID fields are required, the rest are optional. 47 Upon successfully adding an ID, the driver will probe 48 for the device and attempt to bind to it. For example:: 49 50 # echo "8086 10f5" > /sys/bus/pci/drivers/foo/new_id 51 52What: /sys/bus/pci/drivers/.../remove_id 53What: /sys/devices/pciX/.../remove_id 54Date: February 2009 55Contact: Chris Wright <chrisw@sous-sol.org> 56Description: 57 Writing a device ID to this file will remove an ID 58 that was dynamically added via the new_id sysfs entry. 59 The format for the device ID is: 60 VVVV DDDD SVVV SDDD CCCC MMMM. That is Vendor ID, Device 61 ID, Subsystem Vendor ID, Subsystem Device ID, Class, 62 and Class Mask. The Vendor ID and Device ID fields are 63 required, the rest are optional. After successfully 64 removing an ID, the driver will no longer support the 65 device. This is useful to ensure auto probing won't 66 match the driver to the device. For example:: 67 68 # echo "8086 10f5" > /sys/bus/pci/drivers/foo/remove_id 69 70What: /sys/bus/pci/rescan 71Date: January 2009 72Contact: Linux PCI developers <linux-pci@vger.kernel.org> 73Description: 74 Writing a non-zero value to this attribute will 75 force a rescan of all PCI buses in the system, and 76 re-discover previously removed devices. 77 78What: /sys/bus/pci/devices/.../msi_bus 79Date: September 2014 80Contact: Linux PCI developers <linux-pci@vger.kernel.org> 81Description: 82 Writing a zero value to this attribute disallows MSI and 83 MSI-X for any future drivers of the device. If the device 84 is a bridge, MSI and MSI-X will be disallowed for future 85 drivers of all child devices under the bridge. Drivers 86 must be reloaded for the new setting to take effect. 87 88What: /sys/bus/pci/devices/.../msi_irqs/ 89Date: September, 2011 90Contact: Neil Horman <nhorman@tuxdriver.com> 91Description: 92 The /sys/devices/.../msi_irqs directory contains a variable set 93 of files, with each file being named after a corresponding msi 94 irq vector allocated to that device. 95 96What: /sys/bus/pci/devices/.../msi_irqs/<N> 97Date: September 2011 98Contact: Neil Horman <nhorman@tuxdriver.com> 99Description: 100 This attribute indicates the mode that the irq vector named by 101 the file is in (msi vs. msix) 102 103What: /sys/bus/pci/devices/.../irq 104Date: August 2021 105Contact: Linux PCI developers <linux-pci@vger.kernel.org> 106Description: 107 If a driver has enabled MSI (not MSI-X), "irq" contains the 108 IRQ of the first MSI vector. Otherwise "irq" contains the 109 IRQ of the legacy INTx interrupt. 110 111 "irq" being set to 0 indicates that the device isn't 112 capable of generating legacy INTx interrupts. 113 114What: /sys/bus/pci/devices/.../remove 115Date: January 2009 116Contact: Linux PCI developers <linux-pci@vger.kernel.org> 117Description: 118 Writing a non-zero value to this attribute will 119 hot-remove the PCI device and any of its children. 120 121What: /sys/bus/pci/devices/.../pci_bus/.../rescan 122Date: May 2011 123Contact: Linux PCI developers <linux-pci@vger.kernel.org> 124Description: 125 Writing a non-zero value to this attribute will 126 force a rescan of the bus and all child buses, 127 and re-discover devices removed earlier from this 128 part of the device tree. 129 130What: /sys/bus/pci/devices/.../rescan 131Date: January 2009 132Contact: Linux PCI developers <linux-pci@vger.kernel.org> 133Description: 134 Writing a non-zero value to this attribute will 135 force a rescan of the device's parent bus and all 136 child buses, and re-discover devices removed earlier 137 from this part of the device tree. 138 139What: /sys/bus/pci/devices/.../reset_method 140Date: August 2021 141Contact: Amey Narkhede <ameynarkhede03@gmail.com> 142Description: 143 Some devices allow an individual function to be reset 144 without affecting other functions in the same slot. 145 146 For devices that have this support, a file named 147 reset_method is present in sysfs. Reading this file 148 gives names of the supported and enabled reset methods and 149 their ordering. Writing a space-separated list of names of 150 reset methods sets the reset methods and ordering to be 151 used when resetting the device. Writing an empty string 152 disables the ability to reset the device. Writing 153 "default" enables all supported reset methods in the 154 default ordering. 155 156What: /sys/bus/pci/devices/.../reset 157Date: July 2009 158Contact: Michael S. Tsirkin <mst@redhat.com> 159Description: 160 Some devices allow an individual function to be reset 161 without affecting other functions in the same device. 162 For devices that have this support, a file named reset 163 will be present in sysfs. Writing 1 to this file 164 will perform reset. 165 166What: /sys/bus/pci/devices/.../vpd 167Date: February 2008 168Contact: Ben Hutchings <bwh@kernel.org> 169Description: 170 A file named vpd in a device directory will be a 171 binary file containing the Vital Product Data for the 172 device. It should follow the VPD format defined in 173 PCI Specification 2.1 or 2.2, but users should consider 174 that some devices may have incorrectly formatted data. 175 If the underlying VPD has a writable section then the 176 corresponding section of this file will be writable. 177 178What: /sys/bus/pci/devices/.../virtfn<N> 179Date: March 2009 180Contact: Yu Zhao <yu.zhao@intel.com> 181Description: 182 This symbolic link appears when hardware supports the SR-IOV 183 capability and the Physical Function driver has enabled it. 184 The symbolic link points to the PCI device sysfs entry of the 185 Virtual Function whose index is N (0...MaxVFs-1). 186 187What: /sys/bus/pci/devices/.../dep_link 188Date: March 2009 189Contact: Yu Zhao <yu.zhao@intel.com> 190Description: 191 This symbolic link appears when hardware supports the SR-IOV 192 capability and the Physical Function driver has enabled it, 193 and this device has vendor specific dependencies with others. 194 The symbolic link points to the PCI device sysfs entry of 195 Physical Function this device depends on. 196 197What: /sys/bus/pci/devices/.../physfn 198Date: March 2009 199Contact: Yu Zhao <yu.zhao@intel.com> 200Description: 201 This symbolic link appears when a device is a Virtual Function. 202 The symbolic link points to the PCI device sysfs entry of the 203 Physical Function this device associates with. 204 205What: /sys/bus/pci/devices/.../modalias 206Date: May 2005 207Contact: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 208Description: 209 This attribute indicates the PCI ID of the device object. 210 211 That is in the format: 212 pci:vXXXXXXXXdXXXXXXXXsvXXXXXXXXsdXXXXXXXXbcXXscXXiXX, 213 where: 214 215 - vXXXXXXXX contains the vendor ID; 216 - dXXXXXXXX contains the device ID; 217 - svXXXXXXXX contains the sub-vendor ID; 218 - sdXXXXXXXX contains the subsystem device ID; 219 - bcXX contains the device class; 220 - scXX contains the device subclass; 221 - iXX contains the device class programming interface. 222 223What: /sys/bus/pci/slots/.../module 224Date: June 2009 225Contact: linux-pci@vger.kernel.org 226Description: 227 This symbolic link points to the PCI hotplug controller driver 228 module that manages the hotplug slot. 229 230What: /sys/bus/pci/devices/.../label 231Date: July 2010 232Contact: Narendra K <narendra_k@dell.com>, linux-bugs@dell.com 233Description: 234 Reading this attribute will provide the firmware 235 given name (SMBIOS type 41 string or ACPI _DSM string) of 236 the PCI device. The attribute will be created only 237 if the firmware has given a name to the PCI device. 238 ACPI _DSM string name will be given priority if the 239 system firmware provides SMBIOS type 41 string also. 240Users: 241 Userspace applications interested in knowing the 242 firmware assigned name of the PCI device. 243 244What: /sys/bus/pci/devices/.../index 245Date: July 2010 246Contact: Narendra K <narendra_k@dell.com>, linux-bugs@dell.com 247Description: 248 Reading this attribute will provide the firmware given instance 249 number of the PCI device. Depending on the platform this can 250 be for example the SMBIOS type 41 device type instance or the 251 user-defined ID (UID) on s390. The attribute will be created 252 only if the firmware has given an instance number to the PCI 253 device and that number is guaranteed to uniquely identify the 254 device in the system. 255Users: 256 Userspace applications interested in knowing the 257 firmware assigned device type instance of the PCI 258 device that can help in understanding the firmware 259 intended order of the PCI device. 260 261What: /sys/bus/pci/devices/.../acpi_index 262Date: July 2010 263Contact: Narendra K <narendra_k@dell.com>, linux-bugs@dell.com 264Description: 265 Reading this attribute will provide the firmware 266 given instance (ACPI _DSM instance number) of the PCI device. 267 The attribute will be created only if the firmware has given 268 an instance number to the PCI device. ACPI _DSM instance number 269 will be given priority if the system firmware provides SMBIOS 270 type 41 device type instance also. 271Users: 272 Userspace applications interested in knowing the 273 firmware assigned instance number of the PCI 274 device that can help in understanding the firmware 275 intended order of the PCI device. 276 277What: /sys/bus/pci/devices/.../d3cold_allowed 278Date: July 2012 279Contact: Huang Ying <ying.huang@intel.com> 280Description: 281 d3cold_allowed is bit to control whether the corresponding PCI 282 device can be put into D3Cold state. If it is cleared, the 283 device will never be put into D3Cold state. If it is set, the 284 device may be put into D3Cold state if other requirements are 285 satisfied too. Reading this attribute will show the current 286 value of d3cold_allowed bit. Writing this attribute will set 287 the value of d3cold_allowed bit. 288 289What: /sys/bus/pci/devices/.../sriov_totalvfs 290Date: November 2012 291Contact: Donald Dutile <ddutile@redhat.com> 292Description: 293 This file appears when a physical PCIe device supports SR-IOV. 294 Userspace applications can read this file to determine the 295 maximum number of Virtual Functions (VFs) a PCIe physical 296 function (PF) can support. Typically, this is the value reported 297 in the PF's SR-IOV extended capability structure's TotalVFs 298 element. Drivers have the ability at probe time to reduce the 299 value read from this file via the pci_sriov_set_totalvfs() 300 function. 301 302What: /sys/bus/pci/devices/.../sriov_numvfs 303Date: November 2012 304Contact: Donald Dutile <ddutile@redhat.com> 305Description: 306 This file appears when a physical PCIe device supports SR-IOV. 307 Userspace applications can read and write to this file to 308 determine and control the enablement or disablement of Virtual 309 Functions (VFs) on the physical function (PF). A read of this 310 file will return the number of VFs that are enabled on this PF. 311 A number written to this file will enable the specified 312 number of VFs. A userspace application would typically read the 313 file and check that the value is zero, and then write the number 314 of VFs that should be enabled on the PF; the value written 315 should be less than or equal to the value in the sriov_totalvfs 316 file. A userspace application wanting to disable the VFs would 317 write a zero to this file. The core ensures that valid values 318 are written to this file, and returns errors when values are not 319 valid. For example, writing a 2 to this file when sriov_numvfs 320 is not 0 and not 2 already will return an error. Writing a 10 321 when the value of sriov_totalvfs is 8 will return an error. 322 323What: /sys/bus/pci/devices/.../driver_override 324Date: April 2014 325Contact: Alex Williamson <alex.williamson@redhat.com> 326Description: 327 This file allows the driver for a device to be specified which 328 will override standard static and dynamic ID matching. When 329 specified, only a driver with a name matching the value written 330 to driver_override will have an opportunity to bind to the 331 device. The override is specified by writing a string to the 332 driver_override file (echo pci-stub > driver_override) and 333 may be cleared with an empty string (echo > driver_override). 334 This returns the device to standard matching rules binding. 335 Writing to driver_override does not automatically unbind the 336 device from its current driver or make any attempt to 337 automatically load the specified driver. If no driver with a 338 matching name is currently loaded in the kernel, the device 339 will not bind to any driver. This also allows devices to 340 opt-out of driver binding using a driver_override name such as 341 "none". Only a single driver may be specified in the override, 342 there is no support for parsing delimiters. 343 344What: /sys/bus/pci/devices/.../numa_node 345Date: Oct 2014 346Contact: Prarit Bhargava <prarit@redhat.com> 347Description: 348 This file contains the NUMA node to which the PCI device is 349 attached, or -1 if the node is unknown. The initial value 350 comes from an ACPI _PXM method or a similar firmware 351 source. If that is missing or incorrect, this file can be 352 written to override the node. In that case, please report 353 a firmware bug to the system vendor. Writing to this file 354 taints the kernel with TAINT_FIRMWARE_WORKAROUND, which 355 reduces the supportability of your system. 356 357What: /sys/bus/pci/devices/.../revision 358Date: November 2016 359Contact: Emil Velikov <emil.l.velikov@gmail.com> 360Description: 361 This file contains the revision field of the PCI device. 362 The value comes from device config space. The file is read only. 363 364What: /sys/bus/pci/devices/.../sriov_drivers_autoprobe 365Date: April 2017 366Contact: Bodong Wang<bodong@mellanox.com> 367Description: 368 This file is associated with the PF of a device that 369 supports SR-IOV. It determines whether newly-enabled VFs 370 are immediately bound to a driver. It initially contains 371 1, which means the kernel automatically binds VFs to a 372 compatible driver immediately after they are enabled. If 373 an application writes 0 to the file before enabling VFs, 374 the kernel will not bind VFs to a driver. 375 376 A typical use case is to write 0 to this file, then enable 377 VFs, then assign the newly-created VFs to virtual machines. 378 Note that changing this file does not affect already- 379 enabled VFs. In this scenario, the user must first disable 380 the VFs, write 0 to sriov_drivers_autoprobe, then re-enable 381 the VFs. 382 383 This is similar to /sys/bus/pci/drivers_autoprobe, but 384 affects only the VFs associated with a specific PF. 385 386What: /sys/bus/pci/devices/.../p2pmem/size 387Date: November 2017 388Contact: Logan Gunthorpe <logang@deltatee.com> 389Description: 390 If the device has any Peer-to-Peer memory registered, this 391 file contains the total amount of memory that the device 392 provides (in decimal). 393 394What: /sys/bus/pci/devices/.../p2pmem/available 395Date: November 2017 396Contact: Logan Gunthorpe <logang@deltatee.com> 397Description: 398 If the device has any Peer-to-Peer memory registered, this 399 file contains the amount of memory that has not been 400 allocated (in decimal). 401 402What: /sys/bus/pci/devices/.../p2pmem/published 403Date: November 2017 404Contact: Logan Gunthorpe <logang@deltatee.com> 405Description: 406 If the device has any Peer-to-Peer memory registered, this 407 file contains a '1' if the memory has been published for 408 use outside the driver that owns the device. 409 410What: /sys/bus/pci/devices/.../p2pmem/allocate 411Date: August 2022 412Contact: Logan Gunthorpe <logang@deltatee.com> 413Description: 414 This file allows mapping p2pmem into userspace. For each 415 mmap() call on this file, the kernel will allocate a chunk 416 of Peer-to-Peer memory for use in Peer-to-Peer transactions. 417 This memory can be used in O_DIRECT calls to NVMe backed 418 files for Peer-to-Peer copies. 419 420What: /sys/bus/pci/devices/.../link/clkpm 421 /sys/bus/pci/devices/.../link/l0s_aspm 422 /sys/bus/pci/devices/.../link/l1_aspm 423 /sys/bus/pci/devices/.../link/l1_1_aspm 424 /sys/bus/pci/devices/.../link/l1_2_aspm 425 /sys/bus/pci/devices/.../link/l1_1_pcipm 426 /sys/bus/pci/devices/.../link/l1_2_pcipm 427Date: October 2019 428Contact: Heiner Kallweit <hkallweit1@gmail.com> 429Description: If ASPM is supported for an endpoint, these files can be 430 used to disable or enable the individual power management 431 states. Write y/1/on to enable, n/0/off to disable. 432 433What: /sys/bus/pci/devices/.../power_state 434Date: November 2020 435Contact: Linux PCI developers <linux-pci@vger.kernel.org> 436Description: 437 This file contains the current PCI power state of the device. 438 The value comes from the PCI kernel device state and can be one 439 of: "unknown", "error", "D0", D1", "D2", "D3hot", "D3cold". 440 The file is read only. 441 442What: /sys/bus/pci/devices/.../sriov_vf_total_msix 443Date: January 2021 444Contact: Leon Romanovsky <leonro@nvidia.com> 445Description: 446 This file is associated with a SR-IOV physical function (PF). 447 It contains the total number of MSI-X vectors available for 448 assignment to all virtual functions (VFs) associated with PF. 449 The value will be zero if the device doesn't support this 450 functionality. For supported devices, the value will be 451 constant and won't be changed after MSI-X vectors assignment. 452 453What: /sys/bus/pci/devices/.../sriov_vf_msix_count 454Date: January 2021 455Contact: Leon Romanovsky <leonro@nvidia.com> 456Description: 457 This file is associated with a SR-IOV virtual function (VF). 458 It allows configuration of the number of MSI-X vectors for 459 the VF. This allows devices that have a global pool of MSI-X 460 vectors to optimally divide them between VFs based on VF usage. 461 462 The values accepted are: 463 * > 0 - this number will be reported as the Table Size in the 464 VF's MSI-X capability 465 * < 0 - not valid 466 * = 0 - will reset to the device default value 467 468 The file is writable if the PF is bound to a driver that 469 implements ->sriov_set_msix_vec_count(). 470 471What: /sys/bus/pci/devices/.../resourceN_resize 472Date: September 2022 473Contact: Alex Williamson <alex.williamson@redhat.com> 474Description: 475 These files provide an interface to PCIe Resizable BAR support. 476 A file is created for each BAR resource (N) supported by the 477 PCIe Resizable BAR extended capability of the device. Reading 478 each file exposes the bitmap of available resource sizes: 479 480 # cat resource1_resize 481 00000000000001c0 482 483 The bitmap represents supported resource sizes for the BAR, 484 where bit0 = 1MB, bit1 = 2MB, bit2 = 4MB, etc. In the above 485 example the device supports 64MB, 128MB, and 256MB BAR sizes. 486 487 When writing the file, the user provides the bit position of 488 the desired resource size, for example: 489 490 # echo 7 > resource1_resize 491 492 This indicates to set the size value corresponding to bit 7, 493 128MB. The resulting size is 2 ^ (bit# + 20). This definition 494 matches the PCIe specification of this capability. 495 496 In order to make use of resource resizing, all PCI drivers must 497 be unbound from the device and peer devices under the same 498 parent bridge may need to be soft removed. In the case of 499 VGA devices, writing a resize value will remove low level 500 console drivers from the device. Raw users of pci-sysfs 501 resourceN attributes must be terminated prior to resizing. 502 Success of the resizing operation is not guaranteed. 503