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Diffstat (limited to 'Documentation/ABI/testing/sysfs-bus-css')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-css | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-css b/Documentation/ABI/testing/sysfs-bus-css new file mode 100644 index 000000000..12a733fe3 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-bus-css @@ -0,0 +1,61 @@ +What: /sys/bus/css/devices/.../type +Date: March 2008 +Contact: Cornelia Huck <cornelia.huck@de.ibm.com> + 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: Cornelia Huck <cornelia.huck@de.ibm.com> + 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: Cornelia Huck <cornelia.huck@de.ibm.com> + 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: Cornelia Huck <cornelia.huck@de.ibm.com> + 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: Cornelia Huck <cohuck@redhat.com> + 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. |