patch-2.4.8 linux/Documentation/s390/CommonIO

• 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.
+