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

From: Toshi Kani
Date: Fri Dec 14 2012 - 20:28:52 EST


On Thu, 2012-12-13 at 23:15 +0800, Jiang Liu wrote:
> On 12/13/2012 10:42 PM, Toshi Kani wrote:
> > On Tue, 2012-12-11 at 22:34 +0800, Jiang Liu wrote:
> >> On 12/08/2012 09:08 AM, Toshi Kani wrote:
> >>> On Fri, 2012-12-07 at 13:57 +0800, Jiang Liu wrote:
> >>>> On 2012-12-7 10:57, Toshi Kani wrote:
> >>>>> On Fri, 2012-12-07 at 00:40 +0800, Jiang Liu wrote:
:
> >>>
> >>>> 2) an ACPI based hotplug manager driver, which is a platform independent
> >>>> driver and manages all hotplug slot created by the slot driver.
> >>>
> >>> It is surely impressive work, but I think is is a bit overdoing. I
> >>> expect hot-pluggable servers come with management console and/or GUI
> >>> where a user can manage hardware units and initiate hot-plug operations.
> >>> I do not think the kernel needs to step into such area since it tends to
> >>> be platform-specific.
> >> One of the major usages of this feature is for testing.
> >> It will be hard for OSVs and OEMs to verify hotplug functionalities if it could
> >> only be tested by physical hotplug or through management console. So to pave the
> >> way for hotplug, we need to provide a mechanism for OEMs and OSVs to execute
> >> auto stress tests for hotplug functionalities.
> >
> > Yes, but such OS->FW interface is platform-specific. Some platforms use
> > IPMI for the OS to communicate with the management console. In this
> > case, an OEM-specific command can be used to request a hotplug through
> > IPMI. Some platforms may also support test programs to run on the
> > management console for validations.
> >
> > For early development testing, Yinghai's SCI emulation patch can be used
> > to emulate hotplug events from the OS. It would be part of the kernel
> > debugging features once this patch is accepted.
> Hi Toshi,
> ACPI 5.0 has provided some mechanism to normalize the way to issue
> RAS related requests to firmware. I hope ACPI 5.x will define some standardized
> ways based on the PCC defined in 5.0. If needed, we may provide platform
> specific methods for them too.

Thanks for the pointer! Yeah, the spec purposely does not define the
command. When we support PCC, we will need to provide a way for user
app or oem module to supply a payload.

Thanks,
-Toshi

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