Documentation/s390/CommonIO

   1 S/390 common I/O-Layer - command line parameters and /proc entries
   2 ==================================================================
   3
   4 Command line parameters
   5 -----------------------
   6
   7 * cio_msg = yes | no
   8
   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 0.0.4711 on subchannel 0.0.0042" and "SenseID: Device
  12   0.0.4711 reports: ...".
  13
  14   Default is off.
  15
  16
  17 * cio_ignore = {all} |
  18                {<device> | <range of devices>} |
  19                {!<device> | !<range of devices>}
  20
  21   The given devices will be ignored by the common I/O-layer; no detection
  22   and device sensing will be done on any of those devices. The subchannel to
  23   which the device in question is attached will be treated as if no device was
  24   attached.
  25
  26   An ignored device can be un-ignored later; see the "/proc entries"-section for
  27   details.
  28
  29   The devices must be given either as bus ids (0.0.abcd) or as hexadecimal
  30   device numbers (0xabcd or abcd, for 2.4 backward compatibility).
  31   You can use the 'all' keyword to ignore all devices.
  32   The '!' operator will cause the I/O-layer to _not_ ignore a device.
  33   The command line is parsed from left to right.
  34
  35   For example,
  36         cio_ignore=0.0.0023-0.0.0042,0.0.4711
  37   will ignore all devices ranging from 0.0.0023 to 0.0.0042 and the device
  38   0.0.4711, if detected.
  39   As another example,
  40         cio_ignore=all,!0.0.4711,!0.0.fd00-0.0.fd02
  41   will ignore all devices but 0.0.4711, 0.0.fd00, 0.0.fd01, 0.0.fd02.
  42
  43   By default, no devices are ignored.
  44
  45
  46 /proc entries
  47 -------------
  48
  49 * /proc/cio_ignore
  50
  51   Lists the ranges of devices (by bus id) which are ignored by common I/O.
  52
  53   You can un-ignore certain or all devices by piping to /proc/cio_ignore.
  54   "free all" will un-ignore all ignored devices,
  55   "free <device range>, <device range>, ..." will un-ignore the specified
  56   devices.
  57
  58   For example, if devices 0.0.0023 to 0.0.0042 and 0.0.4711 are ignored,
  59   - echo free 0.0.0030-0.0.0032 > /proc/cio_ignore
  60     will un-ignore devices 0.0.0030 to 0.0.0032 and will leave devices 0.0.0023
  61     to 0.0.002f, 0.0.0033 to 0.0.0042 and 0.0.4711 ignored;
  62   - echo free 0.0.0041 > /proc/cio_ignore will furthermore un-ignore device
  63     0.0.0041;
  64   - echo free all > /proc/cio_ignore will un-ignore all remaining ignored
  65     devices.
  66
  67   When a device is un-ignored, device recognition and sensing is performed and
  68   the device driver will be notified if possible, so the device will become
  69   available to the system. Note that un-ignoring is performed asynchronously.
  70
  71   You can also add ranges of devices to be ignored by piping to
  72   /proc/cio_ignore; "add <device range>, <device range>, ..." will ignore the
  73   specified devices.
  74
  75   Note: While already known devices can be added to the list of devices to be
  76         ignored, there will be no effect on then. However, if such a device
  77         disappears and then reappears, it will then be ignored.
  78
  79   For example,
  80         "echo add 0.0.a000-0.0.accc, 0.0.af00-0.0.afff > /proc/cio_ignore"
  81   will add 0.0.a000-0.0.accc and 0.0.af00-0.0.afff to the list of ignored
  82   devices.
  83
  84   The devices can be specified either by bus id (0.0.abcd) or, for 2.4 backward
  85   compatibility, by the device number in hexadecimal (0xabcd or abcd).
  86
  87
  88 * /proc/s390dbf/cio_*/ (S/390 debug feature)
  89
  90   Some views generated by the debug feature to hold various debug outputs.
  91
  92   - /proc/s390dbf/cio_crw/sprintf
  93     Messages from the processing of pending channel report words (machine check
  94     handling), which will also show when CONFIG_DEBUG_CRW is defined.
  95
  96   - /proc/s390dbf/cio_msg/sprintf
  97     Various debug messages from the common I/O-layer; generally, messages which
  98     will also show when CONFIG_DEBUG_IO is defined.
  99
 100   - /proc/s390dbf/cio_trace/hex_ascii
 101     Logs the calling of functions in the common I/O-layer and, if applicable,
 102     which subchannel they were called for, as well as dumps of some data
 103     structures (like irb in an error case).
 104
 105   The level of logging can be changed to be more or less verbose by piping to
 106   /proc/s390dbf/cio_*/level a number between 0 and 6; see the documentation on
 107   the S/390 debug feature (Documentation/s390/s390dbf.txt) for details.
 108
 109 * For some of the information present in the /proc filesystem in 2.4 (namely,
 110   /proc/subchannels and /proc/chpids), see driver-model.txt.
 111   Information formerly in /proc/irq_count is now in /proc/interrupts.