[PATCH] s390: cio documentation

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

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

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

  The order on the command line is not important.

  The command line is parsed from left to right.

  For example, 

	cio_ignore=0.0.0023-0.0.0042,0.0.4711

  /proc/cio_ignore; "add <device range>, <device range>, ..." will ignore the

  specified devices.

  Note: Already known devices cannot be ignored.

  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 reappeares, it will then be ignored.

  For example, if device 0.0.abcd is already known and all other devices

  0.0.a000-0.0.afff are not known,

  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.abcc, 0.0.abce-0.0.accc and 0.0.af00-0.0.afff to the

  list of ignored devices and skip 0.0.abcd.

  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 (0.0.abcd) or, for 2.4 backward

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

  - /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.

    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 

  /proc/s390dbf/cio_*/level a number between 0 and 6; see the documentation on