1 What: /sys/bus/css/devices/.../type 2 Date: March 2008 3 Contact: Cornelia Huck <cornelia.huck@de.ibm.com> 4 linux-s390@vger.kernel.org 5 Description: Contains the subchannel type, as reported by the hardware. 6 This attribute is present for all subchannel types. 7 8 What: /sys/bus/css/devices/.../modalias 9 Date: March 2008 10 Contact: Cornelia Huck <cornelia.huck@de.ibm.com> 11 linux-s390@vger.kernel.org 12 Description: 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 16 What: /sys/bus/css/drivers/io_subchannel/.../chpids 17 Date: December 2002 18 Contact: Cornelia Huck <cornelia.huck@de.ibm.com> 19 linux-s390@vger.kernel.org 20 Description: Contains the ids of the channel paths used by this 21 subchannel, as reported by the channel subsystem 22 during subchannel recognition. 23 24 Note: This is an I/O-subchannel specific attribute. 25 Users: s390-tools, HAL 26 27 What: /sys/bus/css/drivers/io_subchannel/.../pimpampom 28 Date: December 2002 29 Contact: Cornelia Huck <cornelia.huck@de.ibm.com> 30 linux-s390@vger.kernel.org 31 Description: Contains the PIM/PAM/POM values, as reported by the 32 channel subsystem when last queried by the common I/O 33 layer (this implies that this attribute is not necessarily 34 in sync with the values current in the channel subsystem). 35 36 Note: This is an I/O-subchannel specific attribute. 37 Users: s390-tools, HAL 38 39 What: /sys/bus/css/devices/.../driver_override 40 Date: June 2019 41 Contact: Cornelia Huck <cohuck@redhat.com> 42 linux-s390@vger.kernel.org 43 Description: This file allows the driver for a device to be specified. When 44 specified, only a driver with a name matching the value written 45 to driver_override will have an opportunity to bind to the 46 device. The override is specified by writing a string to the 47 driver_override file (echo vfio-ccw > driver_override) and 48 may be cleared with an empty string (echo > driver_override). 49 This returns the device to standard matching rules binding. 50 Writing to driver_override does not automatically unbind the 51 device from its current driver or make any attempt to 52 automatically load the specified driver. If no driver with a 53 matching name is currently loaded in the kernel, the device 54 will not bind to any driver. This also allows devices to 55 opt-out of driver binding using a driver_override name such as 56 "none". Only a single driver may be specified in the override, 57 there is no support for parsing delimiters. 58 59 Note that unlike the mechanism of the same name for pci, this 60 file does not allow to override basic matching rules. I.e., 61 the driver must still match the subchannel type of the device. 62