Commit 6fd6e4a4 authored by Cornelia Huck's avatar Cornelia Huck Committed by Linus Torvalds

[PATCH] s390: cio documentation

Some clarifications in the cio documentation.
Signed-off-by: default avatarMartin Schwidefsky <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent 5bdfcfcc
......@@ -30,7 +30,7 @@ Command line parameters
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,
......@@ -72,13 +72,14 @@ Command line parameters
/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
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).
......@@ -98,7 +99,8 @@ Command line parameters
- /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
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