1 ======================
2 S/390 common I/O-Layer
3 ======================
4
5 command line parameters, procfs and debugfs en
6 ==============================================
7
8 Command line parameters
9 -----------------------
10
11 * ccw_timeout_log
12
13 Enable logging of debug information in case
14
15 * cio_ignore = device[,device[,..]]
16
17 device := {all | [!]ipldev | [!]condev
18
19 The given devices will be ignored by the com
20 and device sensing will be done on any of th
21 which the device in question is attached wil
22 attached.
23
24 An ignored device can be un-ignored later; s
25 details.
26
27 The devices must be given either as bus ids
28 device numbers (0xabcd or abcd, for 2.4 back
29 give a device number 0xabcd, it will be inte
30
31 You can use the 'all' keyword to ignore all
32 keywords can be used to refer to the CCW bas
33 device respectively (these are probably usef
34 operator). The '!' operator will cause the I
35 The command line
36 is parsed from left to right.
37
38 For example::
39
40 cio_ignore=0.0.0023-0.0.0042,0.0.4711
41
42 will ignore all devices ranging from 0.0.002
43 0.0.4711, if detected.
44
45 As another example::
46
47 cio_ignore=all,!0.0.4711,!0.0.fd00-0.0
48
49 will ignore all devices but 0.0.4711, 0.0.fd
50
51 By default, no devices are ignored.
52
53
54 /proc entries
55 -------------
56
57 * /proc/cio_ignore
58
59 Lists the ranges of devices (by bus id) whic
60
61 You can un-ignore certain or all devices by
62 "free all" will un-ignore all ignored device
63 "free <device range>, <device range>, ..." w
64 devices.
65
66 For example, if devices 0.0.0023 to 0.0.0042
67
68 - echo free 0.0.0030-0.0.0032 > /proc/cio_ig
69 will un-ignore devices 0.0.0030 to 0.0.003
70 to 0.0.002f, 0.0.0033 to 0.0.0042 and 0.0.
71 - echo free 0.0.0041 > /proc/cio_ignore will
72 0.0.0041;
73 - echo free all > /proc/cio_ignore will un-i
74 devices.
75
76 When a device is un-ignored, device recognit
77 the device driver will be notified if possib
78 available to the system. Note that un-ignori
79
80 You can also add ranges of devices to be ign
81 /proc/cio_ignore; "add <device range>, <devi
82 specified devices.
83
84 Note: While already known devices can be add
85 ignored, there will be no effect on th
86 disappears and then reappears, it will
87 known devices go away, you need the "p
88
89 For example::
90
91 "echo add 0.0.a000-0.0.accc, 0.0.af00-
92
93 will add 0.0.a000-0.0.accc and 0.0.af00-0.0.
94 devices.
95
96 You can remove already known but now ignored
97
98 "echo purge > /proc/cio_ignore"
99
100 All devices ignored but still registered and
101 will be deregistered and thus removed from t
102
103 The devices can be specified either by bus i
104 compatibility, by the device number in hexad
105 numbers given as 0xabcd will be interpreted
106
107 * /proc/cio_settle
108
109 A write request to this file is blocked unti
110 handled. This will allow userspace to wait f
111 device availability after changing cio_ignor
112
113 * For some of the information present in the /
114 /proc/subchannels and /proc/chpids), see dri
115 Information formerly in /proc/irq_count is n
116
117
118 debugfs entries
119 ---------------
120
121 * /sys/kernel/debug/s390dbf/cio_*/ (S/390 debu
122
123 Some views generated by the debug feature to
124
125 - /sys/kernel/debug/s390dbf/cio_crw/sprintf
126 Messages from the processing of pending ch
127 handling).
128
129 - /sys/kernel/debug/s390dbf/cio_msg/sprintf
130 Various debug messages from the common I/O
131
132 - /sys/kernel/debug/s390dbf/cio_trace/hex_as
133 Logs the calling of functions in the commo
134 which subchannel they were called for, as
135 structures (like irb in an error case).
136
137 The level of logging can be changed to be mo
138 /sys/kernel/debug/s390dbf/cio_*/level a numb
139 documentation on the S/390 debug feature (Do
140 for details.
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