1 What: /sys/bus/css/devices/.../type 1 What: /sys/bus/css/devices/.../type
2 Date: March 2008 2 Date: March 2008
3 Contact: linux-s390@vger.kernel.org !! 3 Contact: Cornelia Huck <cornelia.huck@de.ibm.com>
>> 4 linux-s390@vger.kernel.org
4 Description: Contains the subchannel type, 5 Description: Contains the subchannel type, as reported by the hardware.
5 This attribute is present for 6 This attribute is present for all subchannel types.
6 7
7 What: /sys/bus/css/devices/.../modal 8 What: /sys/bus/css/devices/.../modalias
8 Date: March 2008 9 Date: March 2008
9 Contact: linux-s390@vger.kernel.org !! 10 Contact: Cornelia Huck <cornelia.huck@de.ibm.com>
>> 11 linux-s390@vger.kernel.org
10 Description: Contains the module alias as r 12 Description: Contains the module alias as reported with uevents.
11 It is of the format css:t<type 13 It is of the format css:t<type> and present for all
12 subchannel types. 14 subchannel types.
13 15
14 What: /sys/bus/css/drivers/io_subcha 16 What: /sys/bus/css/drivers/io_subchannel/.../chpids
15 Date: December 2002 17 Date: December 2002
16 Contact: linux-s390@vger.kernel.org !! 18 Contact: Cornelia Huck <cornelia.huck@de.ibm.com>
>> 19 linux-s390@vger.kernel.org
17 Description: Contains the ids of the channe 20 Description: Contains the ids of the channel paths used by this
18 subchannel, as reported by the 21 subchannel, as reported by the channel subsystem
19 during subchannel recognition. 22 during subchannel recognition.
20 23
21 Note: This is an I/O-subchanne 24 Note: This is an I/O-subchannel specific attribute.
22 Users: s390-tools, HAL 25 Users: s390-tools, HAL
23 26
24 What: /sys/bus/css/drivers/io_subcha 27 What: /sys/bus/css/drivers/io_subchannel/.../pimpampom
25 Date: December 2002 28 Date: December 2002
26 Contact: linux-s390@vger.kernel.org !! 29 Contact: Cornelia Huck <cornelia.huck@de.ibm.com>
>> 30 linux-s390@vger.kernel.org
27 Description: Contains the PIM/PAM/POM value 31 Description: Contains the PIM/PAM/POM values, as reported by the
28 channel subsystem when last qu 32 channel subsystem when last queried by the common I/O
29 layer (this implies that this 33 layer (this implies that this attribute is not necessarily
30 in sync with the values curren 34 in sync with the values current in the channel subsystem).
31 35
32 Note: This is an I/O-subchanne 36 Note: This is an I/O-subchannel specific attribute.
33 Users: s390-tools, HAL 37 Users: s390-tools, HAL
34 38
35 What: /sys/bus/css/devices/.../drive 39 What: /sys/bus/css/devices/.../driver_override
36 Date: June 2019 40 Date: June 2019
37 Contact: linux-s390@vger.kernel.org !! 41 Contact: Cornelia Huck <cohuck@redhat.com>
>> 42 linux-s390@vger.kernel.org
38 Description: This file allows the driver fo 43 Description: This file allows the driver for a device to be specified. When
39 specified, only a driver with 44 specified, only a driver with a name matching the value written
40 to driver_override will have a 45 to driver_override will have an opportunity to bind to the
41 device. The override is specif 46 device. The override is specified by writing a string to the
42 driver_override file (echo vfi 47 driver_override file (echo vfio-ccw > driver_override) and
43 may be cleared with an empty s 48 may be cleared with an empty string (echo > driver_override).
44 This returns the device to sta 49 This returns the device to standard matching rules binding.
45 Writing to driver_override doe 50 Writing to driver_override does not automatically unbind the
46 device from its current driver 51 device from its current driver or make any attempt to
47 automatically load the specifi 52 automatically load the specified driver. If no driver with a
48 matching name is currently loa 53 matching name is currently loaded in the kernel, the device
49 will not bind to any driver. 54 will not bind to any driver. This also allows devices to
50 opt-out of driver binding usin 55 opt-out of driver binding using a driver_override name such as
51 "none". Only a single driver 56 "none". Only a single driver may be specified in the override,
52 there is no support for parsin 57 there is no support for parsing delimiters.
53 58
54 Note that unlike the mechanism 59 Note that unlike the mechanism of the same name for pci, this
55 file does not allow to overrid 60 file does not allow to override basic matching rules. I.e.,
56 the driver must still match th 61 the driver must still match the subchannel type of the device.
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