1S/390 common I/O-Layer - command line parameters, procfs and debugfs entries 2============================================================================ 3 4Command line parameters 5----------------------- 6 7* ccw_timeout_log 8 9 Enable logging of debug information in case of ccw device timeouts. 10 11* 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 23 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 27 You can use the 'all' keyword to ignore all devices. 28 The '!' operator will cause the I/O-layer to _not_ ignore a device. 29 The command line is parsed from left to right. 30 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 65 available to the system. Note that un-ignoring is performed asynchronously. 66 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 71 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 73 disappears and then reappears, it will then be ignored. To make 74 known devices go away, you need the "purge" command (see below). 75 76 For example, 77 "echo add 0.0.a000-0.0.accc, 0.0.af00-0.0.afff > /proc/cio_ignore" 78 will add 0.0.a000-0.0.accc and 0.0.af00-0.0.afff to the list of ignored 79 devices. 80 81 You can remove already known but now ignored devices via 82 "echo purge > /proc/cio_ignore" 83 All devices ignored but still registered and not online (= not in use) 84 will be deregistered and thus removed from the system. 85 86 The devices can be specified either by bus id (0.x.abcd) or, for 2.4 backward 87 compatibility, by the device number in hexadecimal (0xabcd or abcd). Device 88 numbers given as 0xabcd will be interpreted as 0.0.abcd. 89 90* For some of the information present in the /proc filesystem in 2.4 (namely, 91 /proc/subchannels and /proc/chpids), see driver-model.txt. 92 Information formerly in /proc/irq_count is now in /proc/interrupts. 93 94 95debugfs entries 96--------------- 97 98* /sys/kernel/debug/s390dbf/cio_*/ (S/390 debug feature) 99 100 Some views generated by the debug feature to hold various debug outputs. 101 102 - /sys/kernel/debug/s390dbf/cio_crw/sprintf 103 Messages from the processing of pending channel report words (machine check 104 handling). 105 106 - /sys/kernel/debug/s390dbf/cio_msg/sprintf 107 Various debug messages from the common I/O-layer. 108 109 - /sys/kernel/debug/s390dbf/cio_trace/hex_ascii 110 Logs the calling of functions in the common I/O-layer and, if applicable, 111 which subchannel they were called for, as well as dumps of some data 112 structures (like irb in an error case). 113 114 The level of logging can be changed to be more or less verbose by piping to 115 /sys/kernel/debug/s390dbf/cio_*/level a number between 0 and 6; see the 116 documentation on the S/390 debug feature (Documentation/s390/s390dbf.txt) 117 for details. 118