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Diffstat (limited to 'Documentation/watchdog/hpwdt.txt')
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diff --git a/Documentation/watchdog/hpwdt.txt b/Documentation/watchdog/hpwdt.txt deleted file mode 100644 index 9488078900e0..000000000000 --- a/Documentation/watchdog/hpwdt.txt +++ /dev/null @@ -1,95 +0,0 @@ -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 dependent 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 four (4) 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. - 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). - - 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). - - 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 - 3. Once the system comes up perform a rmmod hpwdt - 4. insmod /lib/modules/`uname -r`/kernel/drivers/char/watchdog/hpwdt.ko priority=1 - - 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) |