What: /sys/bus/css/devices/.../type Date: March 2008 Contact: linux-s390@vger.kernel.org Description: Contains the subchannel type, as reported by the hardware. This attribute is present for all subchannel types. What: /sys/bus/css/devices/.../modalias Date: March 2008 Contact: linux-s390@vger.kernel.org Description: Contains the module alias as reported with uevents. It is of the format css:t and present for all subchannel types. What: /sys/bus/css/drivers/io_subchannel/.../chpids Date: December 2002 Contact: linux-s390@vger.kernel.org Description: Contains the ids of the channel paths used by this subchannel, as reported by the channel subsystem during subchannel recognition. Note: This is an I/O-subchannel specific attribute. Users: s390-tools, HAL What: /sys/bus/css/drivers/io_subchannel/.../pimpampom Date: December 2002 Contact: linux-s390@vger.kernel.org Description: Contains the PIM/PAM/POM values, as reported by the channel subsystem when last queried by the common I/O layer (this implies that this attribute is not necessarily in sync with the values current in the channel subsystem). Note: This is an I/O-subchannel specific attribute. Users: s390-tools, HAL What: /sys/bus/css/devices/.../driver_override Date: June 2019 Contact: linux-s390@vger.kernel.org Description: This file allows the driver for a device to be specified. When specified, only a driver with a name matching the value written to driver_override will have an opportunity to bind to the device. The override is specified by writing a string to the driver_override file (echo vfio-ccw > driver_override) and may be cleared with an empty string (echo > driver_override). This returns the device to standard matching rules binding. Writing to driver_override does not automatically unbind the device from its current driver or make any attempt to automatically load the specified driver. If no driver with a matching name is currently loaded in the kernel, the device will not bind to any driver. This also allows devices to opt-out of driver binding using a driver_override name such as "none". Only a single driver may be specified in the override, there is no support for parsing delimiters. Note that unlike the mechanism of the same name for pci, this file does not allow to override basic matching rules. I.e., the driver must still match the subchannel type of the device.