patch-2.4.8 linux/Documentation/s390/CommonIO
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- Lines: 125
- Date:
Wed Jul 25 14:12:01 2001
- Orig file:
v2.4.7/linux/Documentation/s390/CommonIO
- Orig date:
Wed Dec 31 16:00:00 1969
diff -u --recursive --new-file v2.4.7/linux/Documentation/s390/CommonIO linux/Documentation/s390/CommonIO
@@ -0,0 +1,124 @@
+S/390 common I/O-Layer - command line parameters and /proc entries
+==================================================================
+
+Command line parameters
+-----------------------
+
+* cio_msg = yes | no
+
+ Determines whether information on found devices and sensed device
+ characteristics should be shown during startup, i. e. messages of the types
+ "Detected device 4711 on subchannel 42" and "SenseID: Device 4711 reports: ...".
+
+ Default is off.
+
+
+* cio_notoper_msg = yes | no
+
+ Determines whether messages of the type "Device 4711 became 'not operational'"
+ should be shown during startup; after startup, they will always be shown.
+
+ Default is on.
+
+
+* cio_ignore = <range of device numbers>, <range of device numbers>, ...
+
+ The given device numbers will be ignored by the common I/O-layer; no detection
+ and device sensing will be done on any of those devices. The subchannel to
+ which the device in question is attached will be treated as if no device was
+ attached.
+
+ An ignored device can be un-ignored later; see the "/proc entries"-section for
+ details.
+
+ The device numbers must be given hexadecimal.
+
+ For example,
+ cio_ignore=0x23-0x42,0x4711
+ will ignore all devices with device numbers ranging from 23 to 42 and the
+ device with device number 4711, if detected.
+
+ By default, no devices are ignored.
+
+
+* cio_proc_devinfo = yes | no
+
+ Determines whether the entries under /proc/deviceinfo/ (see below) should be
+ created. Since there are problems with systems with many devices attached, I
+ made it configurable.
+
+ Until the problems are dealt with, default is off.
+
+
+/proc entries
+-------------
+
+* /proc/subchannels
+
+ Shows for each subchannel
+ - device number
+ - device type/model and if applicable control unit type/model
+ - whether the device is in use
+ - path installed mask, path available mask, path operational mask and last
+ path used mask
+ - the channel path IDs (chpids)
+
+
+* /proc/deviceinfo/
+
+ Shows in subdirectories for each device some characteristics:
+ - /proc/deviceinfo/<devno>/chpids:
+ the channel path IDs
+ - /proc/deviceinfo/<devno>/in_use:
+ whether the device is in use
+ - /proc/deviceinfo/<devno>/sensedata:
+ the device type/model and if applicable control unit type/model of the
+ device
+
+ NOTE: Since the number of inodes which can be dynamically allocated by procfs
+ is limited, device entries will only be created up to a magic number of
+ devices. The kernel will utter a warning that not all entries can be
+ created. In this case, you shouldn't use "cio_proc_devinfo=yes" (see
+ above).
+
+* /proc/cio_ignore
+
+ Lists the ranges of device numbers which are ignored by common I/O.
+
+ You can un-ignore certain or all devices by piping to /proc/cio_ignore.
+ "free all" will un-ignore all ignored devices,
+ "free <devnorange>, <devnorange>, ..." will un-ignore the specified devices.
+
+ For example, if devices 23 to 42 and 4711 are ignored,
+ - echo free 0x30-0x32 > /proc/cio_ignore
+ will un-ignore devices 30 to 32 and will leave devices 23 to 2F, 33 to 42
+ and 4711 ignored;
+ - echo free 0x41 > /proc/cio_ignore will furthermore un-ignore device 41;
+ - echo free all > /proc/cio_ignore will un-ignore all remaining ignored
+ devices.
+
+ When a device is un-ignored, device recognition and sensing is performed and
+ the device driver will be notified if possible, so the device will become
+ available to the system.
+
+
+* /proc/s390dbf/cio_*/ (S/390 debug feature)
+
+ Some views generated by the debug feature to hold various debug outputs.
+
+ - /proc/s390dbf/cio_crw/sprintf
+ Messages from the processing of pending channel report words (machine check
+ handling), which will also show when CONFIG_DEBUG_CRW is defined.
+
+ - /proc/s390dbf/cio_msg/sprintf
+ Various debug messages from the common I/O-layer; generally, messages which
+ will also show when CONFIG_DEBUG_IO is defined.
+
+ - /proc/s390dbf/cio_trace/hex_ascii
+ Logs the calling of functions in the common I/O-layer and, if applicable,
+ which subchannel they were called for.
+
+ The level of logging can be changed to be more or less verbose by piping to
+ /proc/s390dbf/cio_*/level a number between 0 and 6; see the documentation on
+ the S/390 debug feature (Documentation/s390/s390dbf.txt) for details.
+
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