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Cornelia Huck3952c8d2007-10-12 16:11:25 +02001S/390 common I/O-Layer - command line parameters, procfs and debugfs entries
2============================================================================
Linus Torvalds1da177e2005-04-16 15:20:36 -07003
4Command line parameters
5-----------------------
6
Sebastian Ott14ff56b2008-01-26 14:10:37 +01007* ccw_timeout_log
8
9 Enable logging of debug information in case of ccw device timeouts.
10
Linus Torvalds1da177e2005-04-16 15:20:36 -070011* cio_ignore = {all} |
12 {<device> | <range of devices>} |
13 {!<device> | !<range of devices>}
14
15 The given devices will be ignored by the common I/O-layer; no detection
16 and device sensing will be done on any of those devices. The subchannel to
17 which the device in question is attached will be treated as if no device was
18 attached.
19
20 An ignored device can be un-ignored later; see the "/proc entries"-section for
21 details.
22
Cornelia Huck3952c8d2007-10-12 16:11:25 +020023 The devices must be given either as bus ids (0.x.abcd) or as hexadecimal
24 device numbers (0xabcd or abcd, for 2.4 backward compatibility). If you
25 give a device number 0xabcd, it will be interpreted as 0.0.abcd.
26
Linus Torvalds1da177e2005-04-16 15:20:36 -070027 You can use the 'all' keyword to ignore all devices.
28 The '!' operator will cause the I/O-layer to _not_ ignore a device.
Cornelia Huck6fd6e4a2005-06-21 17:16:27 -070029 The command line is parsed from left to right.
Linus Torvalds1da177e2005-04-16 15:20:36 -070030
31 For example,
32 cio_ignore=0.0.0023-0.0.0042,0.0.4711
33 will ignore all devices ranging from 0.0.0023 to 0.0.0042 and the device
34 0.0.4711, if detected.
35 As another example,
36 cio_ignore=all,!0.0.4711,!0.0.fd00-0.0.fd02
37 will ignore all devices but 0.0.4711, 0.0.fd00, 0.0.fd01, 0.0.fd02.
38
39 By default, no devices are ignored.
40
41
42/proc entries
43-------------
44
45* /proc/cio_ignore
46
47 Lists the ranges of devices (by bus id) which are ignored by common I/O.
48
49 You can un-ignore certain or all devices by piping to /proc/cio_ignore.
50 "free all" will un-ignore all ignored devices,
51 "free <device range>, <device range>, ..." will un-ignore the specified
52 devices.
53
54 For example, if devices 0.0.0023 to 0.0.0042 and 0.0.4711 are ignored,
55 - echo free 0.0.0030-0.0.0032 > /proc/cio_ignore
56 will un-ignore devices 0.0.0030 to 0.0.0032 and will leave devices 0.0.0023
57 to 0.0.002f, 0.0.0033 to 0.0.0042 and 0.0.4711 ignored;
58 - echo free 0.0.0041 > /proc/cio_ignore will furthermore un-ignore device
59 0.0.0041;
60 - echo free all > /proc/cio_ignore will un-ignore all remaining ignored
61 devices.
62
63 When a device is un-ignored, device recognition and sensing is performed and
64 the device driver will be notified if possible, so the device will become
Cornelia Huck9b10fe52006-10-18 18:30:55 +020065 available to the system. Note that un-ignoring is performed asynchronously.
Linus Torvalds1da177e2005-04-16 15:20:36 -070066
67 You can also add ranges of devices to be ignored by piping to
68 /proc/cio_ignore; "add <device range>, <device range>, ..." will ignore the
69 specified devices.
70
Cornelia Huck6fd6e4a2005-06-21 17:16:27 -070071 Note: While already known devices can be added to the list of devices to be
72 ignored, there will be no effect on then. However, if such a device
Nicolas Kaiser2254f5a2006-12-04 15:40:23 +010073 disappears and then reappears, it will then be ignored.
Linus Torvalds1da177e2005-04-16 15:20:36 -070074
Cornelia Huck6fd6e4a2005-06-21 17:16:27 -070075 For example,
Linus Torvalds1da177e2005-04-16 15:20:36 -070076 "echo add 0.0.a000-0.0.accc, 0.0.af00-0.0.afff > /proc/cio_ignore"
Cornelia Huck6fd6e4a2005-06-21 17:16:27 -070077 will add 0.0.a000-0.0.accc and 0.0.af00-0.0.afff to the list of ignored
78 devices.
Linus Torvalds1da177e2005-04-16 15:20:36 -070079
Cornelia Huck3952c8d2007-10-12 16:11:25 +020080 The devices can be specified either by bus id (0.x.abcd) or, for 2.4 backward
81 compatibility, by the device number in hexadecimal (0xabcd or abcd). Device
82 numbers given as 0xabcd will be interpreted as 0.0.abcd.
83
84* For some of the information present in the /proc filesystem in 2.4 (namely,
85 /proc/subchannels and /proc/chpids), see driver-model.txt.
86 Information formerly in /proc/irq_count is now in /proc/interrupts.
Linus Torvalds1da177e2005-04-16 15:20:36 -070087
88
Cornelia Huck3952c8d2007-10-12 16:11:25 +020089debugfs entries
90---------------
91
92* /sys/kernel/debug/s390dbf/cio_*/ (S/390 debug feature)
Linus Torvalds1da177e2005-04-16 15:20:36 -070093
94 Some views generated by the debug feature to hold various debug outputs.
95
Cornelia Huck3952c8d2007-10-12 16:11:25 +020096 - /sys/kernel/debug/s390dbf/cio_crw/sprintf
Linus Torvalds1da177e2005-04-16 15:20:36 -070097 Messages from the processing of pending channel report words (machine check
Cornelia Huck3952c8d2007-10-12 16:11:25 +020098 handling).
Linus Torvalds1da177e2005-04-16 15:20:36 -070099
Cornelia Huck3952c8d2007-10-12 16:11:25 +0200100 - /sys/kernel/debug/s390dbf/cio_msg/sprintf
101 Various debug messages from the common I/O-layer, including messages
102 printed when cio_msg=yes.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103
Cornelia Huck3952c8d2007-10-12 16:11:25 +0200104 - /sys/kernel/debug/s390dbf/cio_trace/hex_ascii
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105 Logs the calling of functions in the common I/O-layer and, if applicable,
Cornelia Huck6fd6e4a2005-06-21 17:16:27 -0700106 which subchannel they were called for, as well as dumps of some data
107 structures (like irb in an error case).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108
109 The level of logging can be changed to be more or less verbose by piping to
Cornelia Huck3952c8d2007-10-12 16:11:25 +0200110 /sys/kernel/debug/s390dbf/cio_*/level a number between 0 and 6; see the
111 documentation on the S/390 debug feature (Documentation/s390/s390dbf.txt)
112 for details.