[SCSI] hpsa: export resettable host attribute

This attribute, requested by Redhat, allows kexec-tools to know
whether the controller can honor the reset_devices kernel parameter
and actually reset the controller.  For kdump to work properly it
is necessary that the reset_devices parameter be honored.  This
attribute enables kexec-tools to warn the user if they attempt to
designate a non-resettable controller as the dump device.

Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 12 insertions, 0 deletions

diff --git a/Documentation/scsi/hpsa.txt b/Documentation/scsi/hpsa.txt
index 880c085b951b..891435a72fce 100644
--- a/Documentation/scsi/hpsa.txt
+++ b/Documentation/scsi/hpsa.txt
@@ -45,6 +45,7 @@ HPSA specific entries in /sys
 
   /sys/class/scsi_host/host*/rescan
   /sys/class/scsi_host/host*/firmware_revision
+  /sys/class/scsi_host/host*/resettable
   /sys/class/scsi_host/host*/transport_mode
 
   the host "rescan" attribute is a write only attribute.  Writing to this
@@ -66,6 +67,17 @@ HPSA specific entries in /sys
   or "simple" mode.  This is controlled by the "hpsa_simple_mode" module
   parameter.
 
+  The "resettable" read-only attribute indicates whether a particular
+  controller is able to honor the "reset_devices" kernel parameter.  If the
+  device is resettable, this file will contain a "1", otherwise, a "0".  This
+  parameter is used by kdump, for example, to reset the controller at driver
+  load time to eliminate any outstanding commands on the controller and get the
+  controller into a known state so that the kdump initiated i/o will work right
+  and not be disrupted in any way by stale commands or other stale state
+  remaining on the controller from the previous kernel.  This attribute enables
+  kexec tools to warn the user if they attempt to designate a device which is
+  unable to honor the reset_devices kernel parameter as a dump device.
+
   HPSA specific disk attributes:
   ------------------------------