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Date:   Thu, 22 Sep 2022 11:36:35 -0600
From:   rwright@hpe.com
To:     Vladimir Panteleev <git@vladimir.panteleev.md>
Cc:     Wim Van Sebroeck <wim@linux-watchdog.org>,
        Guenter Roeck <linux@roeck-us.net>,
        linux-watchdog@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] watchdog: sp5100_tco: Add "action" module parameter
Message-ID: <20220922173635.GJ18783@rfwz62>
Reply-To: rwright@hpe.com
References: <20220920092721.7686-1-git@vladimir.panteleev.md>
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On Tue, Sep 20, 2022 at 09:27:21AM +0000, Vladimir Panteleev wrote:
> Allow configuring the "action" bit, as documented in [1].
> 
> Previously, the only action supported by this module was to reset the
> system (0).  It can now be configured to power off (1) instead.
> 
> [1]: https://www.amd.com/system/files/TechDocs/44413.pdf

The referenced AMD document 44413 is over 10 years old, and I'm
concerned when I try to line that document up against the newer versions
that are implemented in AMD's EPYC processors, that the bit being
manipulated as SP5100_WDT_ACTION_RESET is effectively reserved in the
newer references, for example:

   https://www.amd.com/system/files/TechDocs/55772-A1-PUB.zip

Is Core::X86::Msr::CpuWdtCfg in the newer document is the same as
WatchDogControl in the cited 44413.pdf? If so, then I would point out
that bit 2 is now included in what is called, CpuWdtTimeBase where
values 2-3H are reserved,  meaning bit 2 effectively must be zero.

-- 
Randy Wright            Hewlett Packard Enterprise
Phone: (970) 898-0998   Mail: rwright@hpe.com