1What: /sys/bus/css/devices/.../type 2Date: March 2008 3Contact: Cornelia Huck <cornelia.huck@de.ibm.com> 4 linux-s390@vger.kernel.org 5Description: Contains the subchannel type, as reported by the hardware. 6 This attribute is present for all subchannel types. 7 8What: /sys/bus/css/devices/.../modalias 9Date: March 2008 10Contact: Cornelia Huck <cornelia.huck@de.ibm.com> 11 linux-s390@vger.kernel.org 12Description: Contains the module alias as reported with uevents. 13 It is of the format css:t<type> and present for all 14 subchannel types. 15 16What: /sys/bus/css/drivers/io_subchannel/.../chpids 17Date: December 2002 18Contact: Cornelia Huck <cornelia.huck@de.ibm.com> 19 linux-s390@vger.kernel.org 20Description: Contains the ids of the channel paths used by this 21 subchannel, as reported by the channel subsystem 22 during subchannel recognition. 23 Note: This is an I/O-subchannel specific attribute. 24Users: s390-tools, HAL 25 26What: /sys/bus/css/drivers/io_subchannel/.../pimpampom 27Date: December 2002 28Contact: Cornelia Huck <cornelia.huck@de.ibm.com> 29 linux-s390@vger.kernel.org 30Description: Contains the PIM/PAM/POM values, as reported by the 31 channel subsystem when last queried by the common I/O 32 layer (this implies that this attribute is not necessarily 33 in sync with the values current in the channel subsystem). 34 Note: This is an I/O-subchannel specific attribute. 35Users: s390-tools, HAL 36 37What: /sys/bus/css/devices/.../driver_override 38Date: June 2019 39Contact: Cornelia Huck <cohuck@redhat.com> 40 linux-s390@vger.kernel.org 41Description: This file allows the driver for a device to be specified. When 42 specified, only a driver with a name matching the value written 43 to driver_override will have an opportunity to bind to the 44 device. The override is specified by writing a string to the 45 driver_override file (echo vfio-ccw > driver_override) and 46 may be cleared with an empty string (echo > driver_override). 47 This returns the device to standard matching rules binding. 48 Writing to driver_override does not automatically unbind the 49 device from its current driver or make any attempt to 50 automatically load the specified driver. If no driver with a 51 matching name is currently loaded in the kernel, the device 52 will not bind to any driver. This also allows devices to 53 opt-out of driver binding using a driver_override name such as 54 "none". Only a single driver may be specified in the override, 55 there is no support for parsing delimiters. 56 Note that unlike the mechanism of the same name for pci, this 57 file does not allow to override basic matching rules. I.e., 58 the driver must still match the subchannel type of the device. 59