[PATCH] ipmi: add power cycle capability

This patch to adds "power cycle" functionality to the IPMI power off module
ipmi_poweroff.  It also contains changes to support procfs control of the
feature.

The power cycle action is considered an optional chassis control in the IPMI
specification.  However, it is definitely useful when the hardware supports
it.  A power cycle is usually required in order to reset a firmware in a bad
state.  This action is critical to allow remote management of servers.

The implementation adds power cycle as optional to the ipmi_poweroff module.
It can be modified dynamically through the proc entry mentioned above.  During
a power down and enabled, the power cycle command is sent to the BMC firmware.
 If it fails either due to non-support or some error, it will retry to send
the command as power off.

Signed-off-by: Christopher A. Poblete <Chris_Poblete@dell.com>
Signed-off-by: Corey Minyard <minyard@acm.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 20 insertions, 0 deletions

diff --git a/Documentation/IPMI.txt b/Documentation/IPMI.txt
index 2f99fe6..84d3d4d 100644
--- a/Documentation/IPMI.txt
+++ b/Documentation/IPMI.txt
@@ -594,3 +594,23 @@ an event generator, the event receiver from the local management
 controller will be queried and the events sent to the SEL on that
 device.  Otherwise, the events go nowhere since there is nowhere to
 send them.
+
+
+Poweroff
+--------
+
+If the poweroff capability is selected, the IPMI driver will install
+a shutdown function into the standard poweroff function pointer.  This
+is in the ipmi_poweroff module.  When the system requests a powerdown,
+it will send the proper IPMI commands to do this.  This is supported on
+several platforms.
+
+There is a module parameter named "poweroff_control" that may either be zero
+(do a power down) or 2 (do a power cycle, power the system off, then power
+it on in a few seconds).  Setting ipmi_poweroff.poweroff_control=x will do
+the same thing on the kernel command line.  The parameter is also available
+via the proc filesystem in /proc/ipmi/poweroff_control.  Note that if the
+system does not support power cycling, it will always to the power off.
+
+Note that if you have ACPI enabled, the system will prefer using ACPI to
+power off.