| b.liu | e958203 | 2025-04-17 19:18:16 +0800 | [diff] [blame^] | 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 | Note: This is an I/O-subchannel specific attribute. |
| 24 | Users: s390-tools, HAL |
| 25 | |
| 26 | What: /sys/bus/css/drivers/io_subchannel/.../pimpampom |
| 27 | Date: December 2002 |
| 28 | Contact: Cornelia Huck <cornelia.huck@de.ibm.com> |
| 29 | linux-s390@vger.kernel.org |
| 30 | Description: 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. |
| 35 | Users: s390-tools, HAL |
| 36 | |
| 37 | What: /sys/bus/css/devices/.../driver_override |
| 38 | Date: June 2019 |
| 39 | Contact: Cornelia Huck <cohuck@redhat.com> |
| 40 | linux-s390@vger.kernel.org |
| 41 | Description: 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. |