1 S/390 common I/O-Layer - command line parameters and /proc entries
2 ==================================================================
4 Command line parameters
5 -----------------------
9 Determines whether information on found devices and sensed device
10 characteristics should be shown during startup, i. e. messages of the types
11 "Detected device 4711 on subchannel 42" and "SenseID: Device 4711 reports: ...".
16 * cio_notoper_msg = yes | no
18 Determines whether messages of the type "Device 4711 became 'not operational'"
19 should be shown during startup; after startup, they will always be shown.
24 * cio_ignore = <range of device numbers>, <range of device numbers>, ...
26 The given device numbers will be ignored by the common I/O-layer; no detection
27 and device sensing will be done on any of those devices. The subchannel to
28 which the device in question is attached will be treated as if no device was
31 An ignored device can be un-ignored later; see the "/proc entries"-section for
34 The device numbers must be given hexadecimal.
37 cio_ignore=0x23-0x42,0x4711
38 will ignore all devices with device numbers ranging from 23 to 42 and the
39 device with device number 4711, if detected.
41 By default, no devices are ignored.
44 * cio_proc_devinfo = yes | no
46 Determines whether the entries under /proc/deviceinfo/ (see below) should be
47 created. Since there are problems with systems with many devices attached, I
50 Until the problems are dealt with, default is off.
58 Shows for each subchannel
60 - device type/model and if applicable control unit type/model
61 - whether the device is in use
62 - path installed mask, path available mask, path operational mask and last
64 - the channel path IDs (chpids)
69 Shows in subdirectories for each device some characteristics:
70 - /proc/deviceinfo/<devno>/chpids:
72 - /proc/deviceinfo/<devno>/in_use:
73 whether the device is in use
74 - /proc/deviceinfo/<devno>/sensedata:
75 the device type/model and if applicable control unit type/model of the
78 NOTE: Since the number of inodes which can be dynamically allocated by procfs
79 is limited, device entries will only be created up to a magic number of
80 devices. The kernel will utter a warning that not all entries can be
81 created. In this case, you shouldn't use "cio_proc_devinfo=yes" (see
86 Lists the ranges of device numbers which are ignored by common I/O.
88 You can un-ignore certain or all devices by piping to /proc/cio_ignore.
89 "free all" will un-ignore all ignored devices,
90 "free <devnorange>, <devnorange>, ..." will un-ignore the specified devices.
92 For example, if devices 23 to 42 and 4711 are ignored,
93 - echo free 0x30-0x32 > /proc/cio_ignore
94 will un-ignore devices 30 to 32 and will leave devices 23 to 2F, 33 to 42
96 - echo free 0x41 > /proc/cio_ignore will furthermore un-ignore device 41;
97 - echo free all > /proc/cio_ignore will un-ignore all remaining ignored
100 When a device is un-ignored, device recognition and sensing is performed and
101 the device driver will be notified if possible, so the device will become
102 available to the system.
104 You can also add ranges of devices to be ignored by piping to
105 /proc/cio_ignore; "add <devnorange>, <devnorange>, ..." will ignore the
108 Note: Already known devices cannot be ignored; this also applies to devices
109 which are gone after a machine check.
111 For example, if device abcd is already known and all other devices a000-afff
112 are not known, "echo add 0xa000-0xaccc, 0xaf00-0xafff > /proc/cio_ignore"
113 will add af00-afff to the list of ignored devices and skip a000-accc.
116 * /proc/s390dbf/cio_*/ (S/390 debug feature)
118 Some views generated by the debug feature to hold various debug outputs.
120 - /proc/s390dbf/cio_crw/sprintf
121 Messages from the processing of pending channel report words (machine check
122 handling), which will also show when CONFIG_DEBUG_CRW is defined.
124 - /proc/s390dbf/cio_msg/sprintf
125 Various debug messages from the common I/O-layer; generally, messages which
126 will also show when CONFIG_DEBUG_IO is defined.
128 - /proc/s390dbf/cio_trace/hex_ascii
129 Logs the calling of functions in the common I/O-layer and, if applicable,
130 which subchannel they were called for.
132 The level of logging can be changed to be more or less verbose by piping to
133 /proc/s390dbf/cio_*/level a number between 0 and 6; see the documentation on
134 the S/390 debug feature (Documentation/s390/s390dbf.txt) for details.
138 This entry counts how many times s390_process_IRQ has been called for each
139 CPU. This info is in /proc/interrupts on other architectures.