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author | Linus Torvalds <torvalds@linux-foundation.org> | 2009-06-18 13:14:10 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-06-18 13:14:10 -0700 |
commit | 9e3e4b1d2d13bead8d52703c82a02b55f108b491 (patch) | |
tree | 69d725323a2da43a571eb218beb7c55fa39f1ff2 /Documentation | |
parent | dcce284a259373f9e5570f2e33f79eca84fcf565 (diff) | |
parent | 47bece87b14b866872b52ff04d469832e4936756 (diff) | |
download | kernel_samsung_crespo-9e3e4b1d2d13bead8d52703c82a02b55f108b491.zip kernel_samsung_crespo-9e3e4b1d2d13bead8d52703c82a02b55f108b491.tar.gz kernel_samsung_crespo-9e3e4b1d2d13bead8d52703c82a02b55f108b491.tar.bz2 |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/wim/linux-2.6-watchdog
* git://git.kernel.org/pub/scm/linux/kernel/git/wim/linux-2.6-watchdog:
[WATCHDOG] hpwdt: Add NMI sourcing
[WATCHDOG] iTCO_wdt: Fix ICH7+ reboot issue.
[WATCHDOG] iTCO_wdt: fix memory corruption when RCBA is disabled by hardware
[WATCHDOG] Correct WDIOF_MAGICCLOSE flag
[WATCHDOG] move platform probe and remove function to devinit and devexit
[WATCHDOG] Some more general cleanup
[WATCHDOG] iTCO_wdt: Cleanup code
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/watchdog/hpwdt.txt | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/Documentation/watchdog/hpwdt.txt b/Documentation/watchdog/hpwdt.txt new file mode 100644 index 0000000..127839e --- /dev/null +++ b/Documentation/watchdog/hpwdt.txt @@ -0,0 +1,84 @@ +Last reviewed: 06/02/2009 + + HP iLO2 NMI Watchdog Driver + NMI sourcing for iLO2 based ProLiant Servers + Documentation and Driver by + Thomas Mingarelli <thomas.mingarelli@hp.com> + + The HP iLO2 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 dependant on one another. + A user can have the NMI sourcing without the watchdog timer and vice-versa. + + 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 + 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 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 + nowayout - basic watchdog parameter that does not allow the timer to + be restarted or an impending ASR to be escaped. + + 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 NMI sourcing capability is disabled when the driver discovers that the + nmi_watchdog is turned on (nmi_watchdog = 1). This is 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 user should reboot with nmi_watchdog=0. + + 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. + 2. reboot the sever + + 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). + + Below is a list of NMIs the HP BIOS understands along with the associated + code (reason): + + No source found 00h + + Uncorrectable Memory Error 01h + + ASR NMI 1Bh + + PCI Parity Error 20h + + NMI Button Press 27h + + SB_BUS_NMI 28h + + ILO Doorbell NMI 29h + + ILO IOP NMI 2Ah + + ILO Watchdog NMI 2Bh + + Proc Throt NMI 2Ch + + Front Side Bus NMI 2Dh + + PCI Express Error 2Fh + + DMA controller NMI 30h + + Hypertransport/CSI Error 31h + + + + -- Tom Mingarelli + (thomas.mingarelli@hp.com) |