Based on kernel version 4.16.1. Page generated on 2018-04-09 11:53 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 * cio_ignore = device[,device[,..]] 12 13 device := {all | [!]ipldev | [!]condev | [!]<devno> | [!]<devno>-<devno>} 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. The 'ipldev' and 'condev' 28 keywords can be used to refer to the CCW based boot device and CCW console 29 device respectively (these are probably useful only when combined with the '!' 30 operator). The '!' operator will cause the I/O-layer to _not_ ignore a device. 31 The command line is parsed from left to right. 32 33 For example, 34 cio_ignore=0.0.0023-0.0.0042,0.0.4711 35 will ignore all devices ranging from 0.0.0023 to 0.0.0042 and the device 36 0.0.4711, if detected. 37 As another example, 38 cio_ignore=all,!0.0.4711,!0.0.fd00-0.0.fd02 39 will ignore all devices but 0.0.4711, 0.0.fd00, 0.0.fd01, 0.0.fd02. 40 41 By default, no devices are ignored. 42 43 44 /proc entries 45 ------------- 46 47 * /proc/cio_ignore 48 49 Lists the ranges of devices (by bus id) which are ignored by common I/O. 50 51 You can un-ignore certain or all devices by piping to /proc/cio_ignore. 52 "free all" will un-ignore all ignored devices, 53 "free <device range>, <device range>, ..." will un-ignore the specified 54 devices. 55 56 For example, if devices 0.0.0023 to 0.0.0042 and 0.0.4711 are ignored, 57 - echo free 0.0.0030-0.0.0032 > /proc/cio_ignore 58 will un-ignore devices 0.0.0030 to 0.0.0032 and will leave devices 0.0.0023 59 to 0.0.002f, 0.0.0033 to 0.0.0042 and 0.0.4711 ignored; 60 - echo free 0.0.0041 > /proc/cio_ignore will furthermore un-ignore device 61 0.0.0041; 62 - echo free all > /proc/cio_ignore will un-ignore all remaining ignored 63 devices. 64 65 When a device is un-ignored, device recognition and sensing is performed and 66 the device driver will be notified if possible, so the device will become 67 available to the system. Note that un-ignoring is performed asynchronously. 68 69 You can also add ranges of devices to be ignored by piping to 70 /proc/cio_ignore; "add <device range>, <device range>, ..." will ignore the 71 specified devices. 72 73 Note: While already known devices can be added to the list of devices to be 74 ignored, there will be no effect on then. However, if such a device 75 disappears and then reappears, it will then be ignored. To make 76 known devices go away, you need the "purge" command (see below). 77 78 For example, 79 "echo add 0.0.a000-0.0.accc, 0.0.af00-0.0.afff > /proc/cio_ignore" 80 will add 0.0.a000-0.0.accc and 0.0.af00-0.0.afff to the list of ignored 81 devices. 82 83 You can remove already known but now ignored devices via 84 "echo purge > /proc/cio_ignore" 85 All devices ignored but still registered and not online (= not in use) 86 will be deregistered and thus removed from the system. 87 88 The devices can be specified either by bus id (0.x.abcd) or, for 2.4 backward 89 compatibility, by the device number in hexadecimal (0xabcd or abcd). Device 90 numbers given as 0xabcd will be interpreted as 0.0.abcd. 91 92 * /proc/cio_settle 93 94 A write request to this file is blocked until all queued cio actions are 95 handled. This will allow userspace to wait for pending work affecting 96 device availability after changing cio_ignore or the hardware configuration. 97 98 * For some of the information present in the /proc filesystem in 2.4 (namely, 99 /proc/subchannels and /proc/chpids), see driver-model.txt. 100 Information formerly in /proc/irq_count is now in /proc/interrupts. 101 102 103 debugfs entries 104 --------------- 105 106 * /sys/kernel/debug/s390dbf/cio_*/ (S/390 debug feature) 107 108 Some views generated by the debug feature to hold various debug outputs. 109 110 - /sys/kernel/debug/s390dbf/cio_crw/sprintf 111 Messages from the processing of pending channel report words (machine check 112 handling). 113 114 - /sys/kernel/debug/s390dbf/cio_msg/sprintf 115 Various debug messages from the common I/O-layer. 116 117 - /sys/kernel/debug/s390dbf/cio_trace/hex_ascii 118 Logs the calling of functions in the common I/O-layer and, if applicable, 119 which subchannel they were called for, as well as dumps of some data 120 structures (like irb in an error case). 121 122 The level of logging can be changed to be more or less verbose by piping to 123 /sys/kernel/debug/s390dbf/cio_*/level a number between 0 and 6; see the 124 documentation on the S/390 debug feature (Documentation/s390/s390dbf.txt) 125 for details.