Re: Intel i8xx watchdog driver

From: Scott Long (scottl_at_freebsd.org)
Date: 03/25/04

  • Next message: Brian O'Shea: "Re: Diagnosing unrecognized hardware" 
    Date: Thu, 25 Mar 2004 14:36:29 -0700
To: Doug Ambrisko <ambrisko@ambrisko.com>

    Doug Ambrisko wrote:
    > Scott Long writes:
    > | Wm. Daryl Hawkins wrote:
    > | > I've written a driver for the Intel i8xx TCO watchdog timer for both
    > | > FreeBSD-CURRENT and FreeBSD-STABLE.
    > |
    > | This is wonderful. I'd be happy to test it and shepherd it in. Does it
    > | support the intel 750x chips also?
    >
    > All ICH chips that I've touched support this with the device ID updated
    > as needed. FYI there is a new watchdog device in the 6300ESB. Not
    > sure if it is in prior ICH chips. It is interesting in that during the
    > first expire it will generate and interrupt then it will reboot on the
    > next expire. So if you have an ICH then you can use it.
    >

    In reading the code, it appears that it is indeed an ICHx service and
    not limited to just i8xx chipsets. I have a few issues with how the
    probe and attach are done, and I'm addressing these in a private mail
    right now. It's funny that I was reading the Intel ICH5 docs last night
    and didn't come across this feature at all.

    I'm not sure if I like the idea of auto-reboot on second expire, unless
    it is configurable (i.e. you can turn that feature off depending on the
    situation). I understand it's purpose though.

    > A nice concept would be to have a SW watchdog based on the clock tickle
    > the HW watchdog. If the SW watchdog goes off you get a panic.
    >
    > Interesting caveats are having the watchdogs going off while in kgdb/ddb.
    >

    Talking with PHK about this now. There seems to be a growing need for a
    mechanism that can inform registered listeners that DDB is about to be
    entered. It's just a random thought in my brain right now, need more
    time to flesh it out.

    > Caveat to the ICH TCO timer is that if the speaker output out of the ICH
    > has a pull up resistor on it then the TCO reset is disabled and will not
    > reset the system. I ran into this on a motherboard at a prior company.
    > You cannot via SW disable this feature :-(
    >
    > I have code for the SIS 630 chipset that I can give to anyone interested.

    More support it wonderful! I don't have any hardware to test it on, though.

    Scott
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  • Next message: Brian O'Shea: "Re: Diagnosing unrecognized hardware"

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