| 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<type> 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. |