mirror of
https://github.com/torvalds/linux.git
synced 2024-12-28 22:02:28 +00:00
879acca58a
This patch introduces a proc file cio_settle. A write request to this file is blocked until all queued cio actions are handled. This will allow userspace to wait for pending work affecting device availability after changing cio_ignore or the hardware configuration. Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
124 lines
4.8 KiB
Plaintext
124 lines
4.8 KiB
Plaintext
S/390 common I/O-Layer - command line parameters, procfs and debugfs entries
|
|
============================================================================
|
|
|
|
Command line parameters
|
|
-----------------------
|
|
|
|
* ccw_timeout_log
|
|
|
|
Enable logging of debug information in case of ccw device timeouts.
|
|
|
|
* cio_ignore = {all} |
|
|
{<device> | <range of devices>} |
|
|
{!<device> | !<range of devices>}
|
|
|
|
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 <device range>, <device range>, ..." 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 <device range>, <device range>, ..." 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. To make
|
|
known devices go away, you need the "purge" command (see below).
|
|
|
|
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.
|
|
|
|
You can remove already known but now ignored devices via
|
|
"echo purge > /proc/cio_ignore"
|
|
All devices ignored but still registered and not online (= not in use)
|
|
will be deregistered and thus removed from the system.
|
|
|
|
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.
|
|
|
|
* /proc/cio_settle
|
|
|
|
A write request to this file is blocked until all queued cio actions are
|
|
handled. This will allow userspace to wait for pending work affecting
|
|
device availability after changing cio_ignore or the hardware configuration.
|
|
|
|
* 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.
|
|
|
|
- /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.
|