diff options
Diffstat (limited to 'Documentation/s390/CommonIO')
| -rw-r--r-- | Documentation/s390/CommonIO | 78 |
1 files changed, 46 insertions, 32 deletions
diff --git a/Documentation/s390/CommonIO b/Documentation/s390/CommonIO index 22f82f21bc6..6e0f63f343b 100644 --- a/Documentation/s390/CommonIO +++ b/Documentation/s390/CommonIO @@ -1,22 +1,16 @@ -S/390 common I/O-Layer - command line parameters and /proc entries -================================================================== +S/390 common I/O-Layer - command line parameters, procfs and debugfs entries +============================================================================ Command line parameters ----------------------- -* cio_msg = yes | no - - Determines whether information on found devices and sensed device - characteristics should be shown during startup, i. e. messages of the types - "Detected device 0.0.4711 on subchannel 0.0.0042" and "SenseID: Device - 0.0.4711 reports: ...". +* ccw_timeout_log - Default is off. + Enable logging of debug information in case of ccw device timeouts. +* cio_ignore = device[,device[,..]] -* cio_ignore = {all} | - {<device> | <range of devices>} | - {!<device> | !<range of devices>} + device := {all | [!]ipldev | [!]condev | [!]<devno> | [!]<devno>-<devno>} The given devices will be ignored by the common I/O-layer; no detection and device sensing will be done on any of those devices. The subchannel to @@ -26,10 +20,14 @@ Command line parameters An ignored device can be un-ignored later; see the "/proc entries"-section for details. - The devices must be given either as bus ids (0.0.abcd) or as hexadecimal - device numbers (0xabcd or abcd, for 2.4 backward compatibility). - You can use the 'all' keyword to ignore all devices. - The '!' operator will cause the I/O-layer to _not_ ignore a device. + The devices must be given either as bus ids (0.x.abcd) or as hexadecimal + device numbers (0xabcd or abcd, for 2.4 backward compatibility). If you + give a device number 0xabcd, it will be interpreted as 0.0.abcd. + + You can use the 'all' keyword to ignore all devices. The 'ipldev' and 'condev' + keywords can be used to refer to the CCW based boot device and CCW console + device respectively (these are probably useful only when combined with the '!' + operator). The '!' operator will cause the I/O-layer to _not_ ignore a device. The command line is parsed from left to right. For example, @@ -74,38 +72,54 @@ Command line parameters Note: While already known devices can be added to the list of devices to be ignored, there will be no effect on then. However, if such a device - disappears and then reappears, it will then be ignored. + disappears and then reappears, it will then be ignored. To make + known devices go away, you need the "purge" command (see below). For example, "echo add 0.0.a000-0.0.accc, 0.0.af00-0.0.afff > /proc/cio_ignore" will add 0.0.a000-0.0.accc and 0.0.af00-0.0.afff to the list of ignored devices. - The devices can be specified either by bus id (0.0.abcd) or, for 2.4 backward - compatibility, by the device number in hexadecimal (0xabcd or abcd). + You can remove already known but now ignored devices via + "echo purge > /proc/cio_ignore" + All devices ignored but still registered and not online (= not in use) + will be deregistered and thus removed from the system. + + The devices can be specified either by bus id (0.x.abcd) or, for 2.4 backward + compatibility, by the device number in hexadecimal (0xabcd or abcd). Device + numbers given as 0xabcd will be interpreted as 0.0.abcd. + +* /proc/cio_settle + + A write request to this file is blocked until all queued cio actions are + handled. This will allow userspace to wait for pending work affecting + device availability after changing cio_ignore or the hardware configuration. +* For some of the information present in the /proc filesystem in 2.4 (namely, + /proc/subchannels and /proc/chpids), see driver-model.txt. + Information formerly in /proc/irq_count is now in /proc/interrupts. -* /proc/s390dbf/cio_*/ (S/390 debug feature) + +debugfs entries +--------------- + +* /sys/kernel/debug/s390dbf/cio_*/ (S/390 debug feature) Some views generated by the debug feature to hold various debug outputs. - - /proc/s390dbf/cio_crw/sprintf + - /sys/kernel/debug/s390dbf/cio_crw/sprintf Messages from the processing of pending channel report words (machine check - handling), which will also show when CONFIG_DEBUG_CRW is defined. + handling). - - /proc/s390dbf/cio_msg/sprintf - Various debug messages from the common I/O-layer; generally, messages which - will also show when CONFIG_DEBUG_IO is defined. + - /sys/kernel/debug/s390dbf/cio_msg/sprintf + Various debug messages from the common I/O-layer. - - /proc/s390dbf/cio_trace/hex_ascii + - /sys/kernel/debug/s390dbf/cio_trace/hex_ascii Logs the calling of functions in the common I/O-layer and, if applicable, which subchannel they were called for, as well as dumps of some data structures (like irb in an error case). The level of logging can be changed to be more or less verbose by piping to - /proc/s390dbf/cio_*/level a number between 0 and 6; see the documentation on - the S/390 debug feature (Documentation/s390/s390dbf.txt) for details. - -* For some of the information present in the /proc filesystem in 2.4 (namely, - /proc/subchannels and /proc/chpids), see driver-model.txt. - Information formerly in /proc/irq_count is now in /proc/interrupts. + /sys/kernel/debug/s390dbf/cio_*/level a number between 0 and 6; see the + documentation on the S/390 debug feature (Documentation/s390/s390dbf.txt) + for details. |