Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

S/390 common I/O-Layer - command line parameters, procfs and debugfs entries

============================================================================

Command line parameters

-----------------------

* cio_msg = yes | no

  Determines whether information on found devices and sensed device

  characteristics should be shown during startup or when new devices are

  found, i. e. messages of the types "Detected device 0.0.4711 on subchannel

  0.0.0042" and "SenseID: Device 0.0.4711 reports: ...".

  Default is off.

* cio_ignore = {all} |

               { | } |

               {! | !}

  The given devices 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 devices must be given either as bus ids (0.x.abcd) or as hexadecimal

  device numbers (0xabcd or abcd, for 2.4 backward compatibility). If you

  give a device number 0xabcd, it will be interpreted as 0.0.abcd.

  You can use the 'all' keyword to ignore all devices.

  The '!' operator will cause the I/O-layer to _not_ ignore a device.

  The command line is parsed from left to right.

  For example,

        cio_ignore=0.0.0023-0.0.0042,0.0.4711

  will ignore all devices ranging from 0.0.0023 to 0.0.0042 and the device

  0.0.4711, if detected.

  As another example,

        cio_ignore=all,!0.0.4711,!0.0.fd00-0.0.fd02

  will ignore all devices but 0.0.4711, 0.0.fd00, 0.0.fd01, 0.0.fd02.

  By default, no devices are ignored.

/proc entries

-------------

* /proc/cio_ignore

  Lists the ranges of devices (by bus id) 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 , , ..." will un-ignore the specified

  devices.

  For example, if devices 0.0.0023 to 0.0.0042 and 0.0.4711 are ignored,

  - echo free 0.0.0030-0.0.0032 > /proc/cio_ignore

    will un-ignore devices 0.0.0030 to 0.0.0032 and will leave devices 0.0.0023

    to 0.0.002f, 0.0.0033 to 0.0.0042 and 0.0.4711 ignored;

  - echo free 0.0.0041 > /proc/cio_ignore will furthermore un-ignore device

    0.0.0041;

  - 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. Note that un-ignoring is performed asynchronously.

  You can also add ranges of devices to be ignored by piping to

  /proc/cio_ignore; "add , , ..." will ignore the

  specified devices.

  Note: While already known devices can be added to the list of devices to be

        ignored, there will be no effect on then. However, if such a device

        disappears and then reappears, it will then be ignored.

  For example,

        "echo add 0.0.a000-0.0.accc, 0.0.af00-0.0.afff > /proc/cio_ignore"

  will add 0.0.a000-0.0.accc and 0.0.af00-0.0.afff to the list of ignored

  devices.

  The devices can be specified either by bus id (0.x.abcd) or, for 2.4 backward

  compatibility, by the device number in hexadecimal (0xabcd or abcd). Device

  numbers given as 0xabcd will be interpreted as 0.0.abcd.

* For some of the information present in the /proc filesystem in 2.4 (namely,

  /proc/subchannels and /proc/chpids), see driver-model.txt.

  Information formerly in /proc/irq_count is now in /proc/interrupts.

debugfs entries

---------------

* /sys/kernel/debug/s390dbf/cio_*/ (S/390 debug feature)

  Some views generated by the debug feature to hold various debug outputs.

  - /sys/kernel/debug/s390dbf/cio_crw/sprintf

    Messages from the processing of pending channel report words (machine check

    handling).

  - /sys/kernel/debug/s390dbf/cio_msg/sprintf

    Various debug messages from the common I/O-layer, including messages

    printed when cio_msg=yes.

  - /sys/kernel/debug/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, as well as dumps of some data

    structures (like irb in an error case).

  The level of logging can be changed to be more or less verbose by piping to

  /sys/kernel/debug/s390dbf/cio_*/level a number between 0 and 6; see the

  documentation on the S/390 debug feature (Documentation/s390/s390dbf.txt)

  for details.