patch-2.4.22 linux-2.4.22/Documentation/s390/CommonIO

• Lines: 67
• Date: 2003-08-25 04:44:39.000000000 -0700
• Orig file: linux-2.4.21/Documentation/s390/CommonIO
• Orig date: 2001-10-11 09:04:57.000000000 -0700

diff -urN linux-2.4.21/Documentation/s390/CommonIO linux-2.4.22/Documentation/s390/CommonIO
@@ -21,7 +21,8 @@
   Default is on.
 
 
-* cio_ignore = <range of device numbers>, <range of device numbers>, ...
+* cio_ignore = <device number> | <range of device numbers>, 
+	       <device number> | <range of device numbers>, ...
 
   The given device numbers 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 
@@ -55,14 +56,22 @@
 
 * /proc/subchannels
 
-  Shows for each subchannel
-  - device number
-  - device type/model and if applicable control unit type/model
-  - whether the device is in use
-  - path installed mask, path available mask, path operational mask and last 
-    path used mask
-  - the channel path IDs (chpids)
+  This entry shows information on a per-subchannel basis.
 
+  The data is ordered in the following way:
+
+  - device number 
+  - subchannel number 
+  - device type/model (if applicable; if not, this is empty) and control unit 
+    type/model
+  - whether the device is in use (i. e. a device driver has requested ownership 
+    and registered an interrupt handler)
+  - path installed mask (PIM), as reflected by last store subchannel
+  - path available mask (PAM), as reflected by last store subchannel
+  - path operational mask (POM), as reflected by last store subchannel
+  - the channel path IDs (CHPIDs)
+
+  All fields are separated by spaces, the chpids are in blocks of four chpids.
 
 * /proc/deviceinfo/
 
@@ -137,3 +146,26 @@
 
   This entry counts how many times s390_process_IRQ has been called for each 
   CPU. This info is in /proc/interrupts on other architectures.
+
+* /proc/chpids
+
+  This entry will only show up if you specified CONFIG_CHSC=y during kernel
+  config.
+
+  This entry serves a dual purpose:
+ 
+  - show which chpids are currently known to Linux and their status (online,
+    logically offline),
+
+  - toggling known chpids logically online/offline.
+
+  To toggle a known chpid logically offline, do an
+	echo off <chpid> > /proc/chpids
+  <chpid> is interpreted as hex, even if you omit the '0x'.
+  The chpid will be treated by Linux as if it were not online, which can mean 
+  some devices will become unavailable.
+
+  You can toggle a logically offline chpid online again by
+	echo on <chpid> > /proc/chpids
+  If devices became unavailable by toggling the chpid logically offline, they 
+  will become available again after you toggle the chpid online again.