Re: Chassis reset

From: Vijay Khemka <vijaykhemka@fb.com>
To: Ed Tanous <ed@tanous.net>, Patrick Williams <patrick@stwcx.xyz>
Cc: "openbmc@lists.ozlabs.org" <openbmc@lists.ozlabs.org>
Subject: Re: Chassis reset
Date: Wed, 23 Sep 2020 19:55:54 +0000	[thread overview]
Message-ID: <DFDB5C9F-9C02-4A7C-81C7-FDB0170E34F7@fb.com> (raw)
In-Reply-To: <CACWQX81tyY1Wo6a8e4hnk3fvinfV-x3ogRK1q1W5cfx28tpfrw@mail.gmail.com>

On 9/23/20, 12:27 PM, "Ed Tanous" <ed@tanous.net> wrote:

    On Wed, Sep 23, 2020 at 12:10 PM Patrick Williams <patrick@stwcx.xyz> wrote:
    >
    > On Wed, Sep 23, 2020 at 05:45:51AM +0000, Vijay Khemka wrote:
    > >
    > > Yes I have 2 chassis instance xyz/openbmc_project/chassis0 and xyz/openbmc_project/chassis_system0.
    > > Later one is used for AC reset.
    >
    > Can we do a query to see if 'chassis_system0' exists and use it first
    > and then 'chassis0' if not?

    I don't think it's that simple.  The way the dbus APIs are defined,
    one Redfish chassis needs to call the chassis0 path, the other needs
    to call the chassis_system0 path.  We'd need a way to key off which
    one is which.  I haven't seen any entity-manager configs get checked
    in for a "multinode chassis" entity type, so whatever interface we use
    to describe that will probably be what we need to key off to make that
    path distinction.

    >
    > I think we need to do some enhancement to x86-power-control though also
    > to only create this 'chassis_system0' object if configured.  I believe
    > the current code change you did does it always, even if the
    > systemd-target is empty.

    I keep getting the feeling that xyz/openbmc_project/chassis_system0 is
    just overloading what /xyz/openbmc_project/chassis0 is intended to do,
    x86-power-control just had that already defined, so we went another
    direction.  I wonder if we just need to make the "Can I do a real AC
    reset" configurable, and have it change the behavior of
    /xyz/openbmc_project/chassis0 in that case.

When I was doing this patch, I proposed the same to keep chassis0 only and
take appropriate actions on different commands. But it was decided to have
a separate interface for complete chassis after several rounds of discussion.
That's why I added this and also updated phosphor-dbus-interface README
file. @andrew any comments here.

    Also, I'll reiterate that a chassis reset really should be going in a
    separate repo/application from x86-power-control.  x86-power-control
    should be focused on managing the host.

I agree.

    >
    > --
    > Patrick Williams