Have trick, not sure where to document...

[Ravi Pokala]

-----Original Message-----
    Date: Fri, 6 Nov 2020 12:02:56 +0100
    From: Mateusz Piotrowski <0mp at FreeBSD.org>
    To: Poul-Henning Kamp <phk at phk.freebsd.dk>, hackers at freebsd.org
    Subject: Re: Have trick, not sure where to document...
    Message-ID: <6225bae3-0bb4-bd14-51f3-de72eaa4dc98 at FreeBSD.org>
    Content-Type: text/plain; charset=utf-8; format=flowed

    On 11/6/20 11:23 AM, Poul-Henning Kamp wrote:
    > This seems like a genuinely useful trick to have in the tool-box
    > and now I'm trying to find out where in our documentation something
    > like this belongs ?
    >
    > It seems too specialized and with too many sharp edges for the handbook ?
    >
    > Wiki/UEFI seems rather historical...
    >
    > Suggestions ?
    >
    If you can think of a manual page that would be appropriate then it might be nice to but it there. 
    Otherwise, perhaphs the FAQ book (https://www.freebsd.org/doc/en_US.ISO8859-1/books/faq/book.html)?

If the system has IPMI, there are ways to configure it such that it will enable the watchdog during POST, then disable it when it hands off to the OS. At which time, of course, the OS can re-enable it.

Interestingly, it looks like `ipmitool' does not offer a way to set the BMC watchdog configuration, just report, reset, and disable it. But ipmi(4) can configure things, in concert with `watchdogd'. More importantly, the IPMI specs describe how to set different configurations for different stages of operation:

- POST
- POST, after timing out the previous POST
- OS loading (meaning after POST, before watchdog driver takes over)
- OS normal operation (after the watchdog driver is running)

It should be possible to teach ipmi(4) how to configure the timer for POST and OS-load, then have `watchdogd' issue those commands as part of shutdown.

https://www.intel.com/content/www/us/en/products/docs/servers/ipmi/ipmi-second-gen-interface-spec-v2-rev1-1.html ; section 27.

-Ravi (rpokala@)