Message-ID: <1390345596.1792.468.camel@misato.fc.hp.com>
Subject: Re: [Patch v1 1/3] ACPI: add callback prepare() into
 acpi_hotplug_handler
From: Toshi Kani <toshi.kani@hp.com>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Jiang Liu <jiang.liu@linux.intel.com>,
        "Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
        Bjorn Helgaas <bhelgaas@google.com>, Yinghai Lu <yinghai@kernel.org>,
        Yijing Wang <wangyijing@huawei.com>, Len Brown <lenb@kernel.org>,
        Robert Moore <robert.moore@intel.com>, Lv Zheng <lv.zheng@intel.com>,
        linux-acpi@vger.kernel.org, linux-pci@vger.kernel.org,
        linux-kernel@vger.kernel.org, devel@acpica.org
Date: Tue, 21 Jan 2014 16:06:36 -0700
In-Reply-To: <2201697.uqWgsYrLat@vostro.rjw.lan>
References: <1390013297-23462-1-git-send-email-jiang.liu@linux.intel.com>
	 <1390338897.1792.467.camel@misato.fc.hp.com>
	 <2201697.uqWgsYrLat@vostro.rjw.lan>
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On Wed, 2014-01-22 at 00:17 +0100, Rafael J. Wysocki wrote:
> On Tuesday, January 21, 2014 02:14:57 PM Toshi Kani wrote:
> > On Sat, 2014-01-18 at 10:48 +0800, Jiang Liu wrote:
> > > Add callback prepare() into acpi_hotplug_handler, which will get called
> > > at the very beginning of ACPI hotplug event handler. The ACPI core will
> > > ignore the event if prepare() returns NOTIFY_STOP.
> > > 
> > > Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
> > > ---
> > >  drivers/acpi/scan.c     |    4 ++++
> > >  include/acpi/acpi_bus.h |    1 +
> > >  2 files changed, 5 insertions(+)
> > > 
> > > diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
> > > index fd39459..6b0f419 100644
> > > --- a/drivers/acpi/scan.c
> > > +++ b/drivers/acpi/scan.c
> > > @@ -392,6 +392,10 @@ static void acpi_hotplug_notify_cb(acpi_handle handle, u32 type, void *data)
> > >  	struct acpi_device *adev;
> > >  	acpi_status status;
> > >  
> > > +	if (handler->prepare &&
> > > +	    handler->prepare(handle, type, data) == NOTIFY_STOP)
> > > +		return;
> > 
> > The OS is responsible for calling _OST when it is implemented.  So you
> > cannot just return here.  See acpi_hotplug_unsupported(handle, type)
> > next line.  Also, please describe why prepare() needs to be added.
> 
> I don't think it's needed any more, please see:
> 
> http://marc.info/?l=linux-acpi&m=139001691317575&w=2

Oh, I see.  Thanks!
-Toshi

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