Re: [RFC PATCH v3 0/3] acpi: Introduce prepare_remove deviceoperation

From: Toshi Kani
Date: Wed Dec 05 2012 - 17:39:33 EST


On Wed, 2012-12-05 at 20:10 +0800, Hanjun Guo wrote:
> On 2012/12/5 7:23, Toshi Kani wrote:
> > On Tue, 2012-12-04 at 17:16 +0800, Hanjun Guo wrote:
> >> On 2012/12/4 8:10, Toshi Kani wrote:
> >>> On Mon, 2012-12-03 at 12:25 +0800, Hanjun Guo wrote:
> >>>> On 2012/11/30 6:27, Toshi Kani wrote:
> >>>
> >>> If I read the code right, the framework calls ACPI drivers differently
> >>> at boot-time and hot-add as follows. That is, the new entry points are
> >>> called at hot-add only, but .add() is called at both cases. This
> >>> requires .add() to work differently.
> >>
> >> Hi Toshi,
> >> Thanks for your comments!
> >>
> >>>
> >>> Boot : .add()
> >>
> >> Actually, at boot time: .add(), .start()
> >
> > Right.
> >
> >>> Hot-Add : .add(), .pre_configure(), configure(), etc.
> >>
> >> Yes, we did it as you said in the framework. We use .pre_configure(), configure(),
> >> and post_configure() to instead of .start() for better error handling and recovery.
> >
> > I think we should have hot-plug interfaces at the module level, not at
> > the ACPI-internal level. In this way, the interfaces can be
> > platform-neutral and allow any modules to register, which makes it more
> > consistent with the boot-up sequence. It can also allow ordering of the
> > sequence among the registered modules. Right now, we initiate all
> > procedures from ACPI during hot-plug, which I think is inflexible and
> > steps into other module's role.
> >
> > I am also concerned about the slot handling, which is the core piece of
> > the infrastructure and only allows hot-plug operations on ACPI objects
> > where slot objects are previously created by checking _EJ0. The
> > infrastructure should allow hot-plug operations on any objects, and it
> > should not be dependent on the slot design.
> >
> > I have some rough idea, and it may be easier to review / explain if I
> > make some code changes. So, let me prototype it, and send it you all if
> > that works out. Hopefully, it won't take too long.
>
> Great! If any thing I can do, please let me know it.

Cool. Yes, if the prototype turns out to be a good one, we can work
together to improve it. :)

Thanks,
-Toshi

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