[V4] watchdog: hpwdt: Adjust documentation to match latest kernel module parameters

Message ID 5707AFCE.2030306@hpe.com
State New
Headers show

Commit Message

Nigel Croxon April 8, 2016, 1:19 p.m.
From: Nigel Croxon <nigel.croxon@hpe.com>

Date: Wed, 6 Apr 2016 14:40:05 -0400
Subject: [PATCH V4] watchdog: hpwdt: Adjust documentation to match 
latest kernel module parameters

Adjust documentation to match latest kernel module parameters.

V4 - run cleanpatch to remove whitespaces
V3 - Fixed two spelling mistakes.
V2 - Changed insmod / rmmod to modprobe / modprobe -r

Signed-off-by: Nigel Croxon <nigel.croxon@hpe.com>

---
  Documentation/watchdog/hpwdt.txt |   57 
++++++++++++++++++++------------------
  1 files changed, 30 insertions(+), 27 deletions(-)

+       /boot/grub/grub.conf   or
+       /boot/grub/menu.lst
+    For UEFI systems
+      /boot/efi/EFI/distroname/grub.conf   or
+      /boot/efi/efi/distroname/elilo.conf
   2. reboot the sever
- 3. Once the system comes up perform a rmmod hpwdt
- 4. insmod /lib/modules/`uname 
-r`/kernel/drivers/char/watchdog/hpwdt.ko priority=1
+ 3. Once the system comes up perform a modprobe -r hpwdt
+ 4. modprobe /lib/modules/`uname -r`/kernel/drivers/watchdog/hpwdt.ko

   Now, the hpwdt can successfully receive and source the NMI and 
provide a log
- message that details the reason for the NMI (as determined by the HP 
BIOS).
+ message that details the reason for the NMI (as determined by the HPE 
BIOS).

- Below is a list of NMIs the HP BIOS understands along with the associated
+ Below is a list of NMIs the HPE BIOS understands along with the associated
   code (reason):

      No source found                00h
@@ -92,4 +95,4 @@ Last reviewed: 06/02/2009


   -- Tom Mingarelli
-    (thomas.mingarelli@hp.com)
+    (thomas.mingarelli@hpe.com)
-- 
1.7.1

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diff --git a/Documentation/watchdog/hpwdt.txt 
b/Documentation/watchdog/hpwdt.txt
index 9488078..3521e8b 100644
--- a/Documentation/watchdog/hpwdt.txt
+++ b/Documentation/watchdog/hpwdt.txt
@@ -1,64 +1,67 @@ 
-Last reviewed: 06/02/2009
+Last reviewed: 04/04/2016

-                     HP iLO2 NMI Watchdog Driver
-              NMI sourcing for iLO2 based ProLiant Servers
+                     HPE iLO NMI Watchdog Driver
+              NMI sourcing for iLO based ProLiant Servers
                       Documentation and Driver by
-              Thomas Mingarelli <thomas.mingarelli@hp.com>
+              Thomas Mingarelli <thomas.mingarelli@hpe.com>

- The HP iLO2 NMI Watchdog driver is a kernel module that provides basic
+ The HPE iLO NMI Watchdog driver is a kernel module that provides basic
   watchdog functionality and the added benefit of NMI sourcing. Both the
   watchdog functionality and the NMI sourcing capability need to be enabled
   by the user. Remember that the two modes are not dependent on one 
another.
   A user can have the NMI sourcing without the watchdog timer and 
vice-versa.
+ All references to iLO in this document imply it also works on iLO2 and all
+ subsequent generations.

   Watchdog functionality is enabled like any other common watchdog 
driver. That
   is, an application needs to be started that kicks off the watchdog 
timer. A
   basic application exists in the Documentation/watchdog/src directory 
called
   watchdog-test.c. Simply compile the C file and kick it off. If the system
- gets into a bad state and hangs, the HP ProLiant iLO 2 timer register will
+ gets into a bad state and hangs, the HPE ProLiant iLO timer register will
   not be updated in a timely fashion and a hardware system reset (also 
known as
   an Automatic Server Recovery (ASR)) event will occur.

- The hpwdt driver also has four (4) module parameters. They are the 
following:
+ The hpwdt driver also has three (3) module parameters. They are the 
following:

- soft_margin - allows the user to set the watchdog timer value
- allow_kdump - allows the user to save off a kernel dump image after an NMI
+ soft_margin - allows the user to set the watchdog timer value.
+               Default value is 30 seconds.
+ allow_kdump - allows the user to save off a kernel dump image after an 
NMI.
+               Default value is 1/ON
   nowayout    - basic watchdog parameter that does not allow the timer to
                 be restarted or an impending ASR to be escaped.
- priority    - determines whether or not the hpwdt driver is first on the
-               die_notify list to handle NMIs or last. The default value
-               for this module parameter is 0 or LAST. If the user wants to
-               enable NMI sourcing then reload the hpwdt driver with
-               priority=1 (and boot with nmi_watchdog=0).
+               Default value is set when compiling the kernel. If it is set
+               to "Y", then there is no way of disabling the watchdog once
+               it has been started.

   NOTE: More information about watchdog drivers in general, including 
the ioctl
         interface to /dev/watchdog can be found in
         Documentation/watchdog/watchdog-api.txt and Documentation/IPMI.txt.

- The priority parameter was introduced due to other kernel software 
that relied
- on handling NMIs (like oprofile). Keeping hpwdt's priority at 0 (or LAST)
- enables the users of NMIs for non critical events to be work as expected.
-
   The NMI sourcing capability is disabled by default due to the 
inability to
   distinguish between "NMI Watchdog Ticks" and "HW generated NMI 
events" in the
   Linux kernel. What this means is that the hpwdt nmi handler code is 
called
   each time the NMI signal fires off. This could amount to several 
thousands of
   NMIs in a matter of seconds. If a user sees the Linux kernel's "dazed and
   confused" message in the logs or if the system gets into a hung 
state, then
- the hpwdt driver can be reloaded with the "priority" module parameter set
- (priority=1).
+ the hpwdt driver can be reloaded.

   1. If the kernel has not been booted with nmi_watchdog turned off then
-    edit /boot/grub/menu.lst and place the nmi_watchdog=0 at the end of the
-    currently booting kernel line.
+    edit and place the nmi_watchdog=0 at the end of the currently booting
+    kernel line. Depending on your Linux distribution and platform setup:
+    For non-UEFI systems