Based on kernel version 2.6.26. Page generated on 2008-07-16 21:13 EST.
1 S/390 common I/O-Layer - command line parameters, procfs and debugfs entries 2 ============================================================================ 3 4 Command line parameters 5 ----------------------- 6 7 * ccw_timeout_log 8 9 Enable logging of debug information in case of ccw device timeouts. 10 11 12 * cio_msg = yes | no 13 14 Determines whether information on found devices and sensed device 15 characteristics should be shown during startup or when new devices are 16 found, i. e. messages of the types "Detected device 0.0.4711 on subchannel 17 0.0.0042" and "SenseID: Device 0.0.4711 reports: ...". 18 19 Default is off. 20 21 22 * cio_ignore = {all} | 23 {<device> | <range of devices>} | 24 {!<device> | !<range of devices>} 25 26 The given devices will be ignored by the common I/O-layer; no detection 27 and device sensing will be done on any of those devices. The subchannel to 28 which the device in question is attached will be treated as if no device was 29 attached. 30 31 An ignored device can be un-ignored later; see the "/proc entries"-section for 32 details. 33 34 The devices must be given either as bus ids (0.x.abcd) or as hexadecimal 35 device numbers (0xabcd or abcd, for 2.4 backward compatibility). If you 36 give a device number 0xabcd, it will be interpreted as 0.0.abcd. 37 38 You can use the 'all' keyword to ignore all devices. 39 The '!' operator will cause the I/O-layer to _not_ ignore a device. 40 The command line is parsed from left to right. 41 42 For example, 43 cio_ignore=0.0.0023-0.0.0042,0.0.4711 44 will ignore all devices ranging from 0.0.0023 to 0.0.0042 and the device 45 0.0.4711, if detected. 46 As another example, 47 cio_ignore=all,!0.0.4711,!0.0.fd00-0.0.fd02 48 will ignore all devices but 0.0.4711, 0.0.fd00, 0.0.fd01, 0.0.fd02. 49 50 By default, no devices are ignored. 51 52 53 /proc entries 54 ------------- 55 56 * /proc/cio_ignore 57 58 Lists the ranges of devices (by bus id) which are ignored by common I/O. 59 60 You can un-ignore certain or all devices by piping to /proc/cio_ignore. 61 "free all" will un-ignore all ignored devices, 62 "free <device range>, <device range>, ..." will un-ignore the specified 63 devices. 64 65 For example, if devices 0.0.0023 to 0.0.0042 and 0.0.4711 are ignored, 66 - echo free 0.0.0030-0.0.0032 > /proc/cio_ignore 67 will un-ignore devices 0.0.0030 to 0.0.0032 and will leave devices 0.0.0023 68 to 0.0.002f, 0.0.0033 to 0.0.0042 and 0.0.4711 ignored; 69 - echo free 0.0.0041 > /proc/cio_ignore will furthermore un-ignore device 70 0.0.0041; 71 - echo free all > /proc/cio_ignore will un-ignore all remaining ignored 72 devices. 73 74 When a device is un-ignored, device recognition and sensing is performed and 75 the device driver will be notified if possible, so the device will become 76 available to the system. Note that un-ignoring is performed asynchronously. 77 78 You can also add ranges of devices to be ignored by piping to 79 /proc/cio_ignore; "add <device range>, <device range>, ..." will ignore the 80 specified devices. 81 82 Note: While already known devices can be added to the list of devices to be 83 ignored, there will be no effect on then. However, if such a device 84 disappears and then reappears, it will then be ignored. 85 86 For example, 87 "echo add 0.0.a000-0.0.accc, 0.0.af00-0.0.afff > /proc/cio_ignore" 88 will add 0.0.a000-0.0.accc and 0.0.af00-0.0.afff to the list of ignored 89 devices. 90 91 The devices can be specified either by bus id (0.x.abcd) or, for 2.4 backward 92 compatibility, by the device number in hexadecimal (0xabcd or abcd). Device 93 numbers given as 0xabcd will be interpreted as 0.0.abcd. 94 95 * For some of the information present in the /proc filesystem in 2.4 (namely, 96 /proc/subchannels and /proc/chpids), see driver-model.txt. 97 Information formerly in /proc/irq_count is now in /proc/interrupts. 98 99 100 debugfs entries 101 --------------- 102 103 * /sys/kernel/debug/s390dbf/cio_*/ (S/390 debug feature) 104 105 Some views generated by the debug feature to hold various debug outputs. 106 107 - /sys/kernel/debug/s390dbf/cio_crw/sprintf 108 Messages from the processing of pending channel report words (machine check 109 handling). 110 111 - /sys/kernel/debug/s390dbf/cio_msg/sprintf 112 Various debug messages from the common I/O-layer, including messages 113 printed when cio_msg=yes. 114 115 - /sys/kernel/debug/s390dbf/cio_trace/hex_ascii 116 Logs the calling of functions in the common I/O-layer and, if applicable, 117 which subchannel they were called for, as well as dumps of some data 118 structures (like irb in an error case). 119 120 The level of logging can be changed to be more or less verbose by piping to 121 /sys/kernel/debug/s390dbf/cio_*/level a number between 0 and 6; see the 122 documentation on the S/390 debug feature (Documentation/s390/s390dbf.txt) 123 for details.