Subject: Re: [PATCH RFC v2 2/3] ec: add ec space notifier
From: li guang <lig.fnst@cn.fujitsu.com>
To: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Len Brown <lenb@kernel.org>, Matthew Garrett <matthew.garrett@nebula.com>,
        linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org,
        platform-driver-x86@vger.kernel.org,
        Andreas =?ISO-8859-1?Q?F=E4rber?= <afaerber@suse.de>,
        Igor Mammedov <imammedo@redhat.com>
In-Reply-To: <10739719.ouMOhAfYPv@vostro.rjw.lan>
References: <1370482835-764-1-git-send-email-lig.fnst@cn.fujitsu.com>
	 <1370482835-764-3-git-send-email-lig.fnst@cn.fujitsu.com>
	 <10739719.ouMOhAfYPv@vostro.rjw.lan>
Date: Mon, 10 Jun 2013 08:46:54 +0800
Message-ID: <1370825214.21655.20.camel@liguang.fnst.cn.fujitsu.com>
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在 2013-06-06四的 12:59 +0200，Rafael J. Wysocki写道：
> On Thursday, June 06, 2013 09:40:34 AM liguang wrote:
> > add a notifier for anyone who are instresting in
> > ec space changing.
> > 
> > Signed-off-by: liguang <lig.fnst@cn.fujitsu.com>
> 
> I'm not going to apply this anyway, but can you please explain what's the
> problem you're trying to solve here?

OK, currently it is for QEMU to do cpu online automatically after
hot-plug a cpu,
and maybe potentially for real platform's cpu
plug/unplug implementation.
with this notifier, we don't need any GPIOes,IO ports, and other
hardware cost if we do have an EC chip in board to trigger kernel's 
cpu process for this.

Yep, you said you'll reject this anyway,
but I have to ask do this notifier offend
any rules of your development?
or some other reasons?

Thanks!

> 
> > ---
> >  drivers/acpi/ec.c    |   32 ++++++++++++++++++++++++++++++++
> >  include/linux/acpi.h |    2 ++
> >  2 files changed, 34 insertions(+), 0 deletions(-)
> > 
> > diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
> > index edc0081..dee3417 100644
> > --- a/drivers/acpi/ec.c
> > +++ b/drivers/acpi/ec.c
> > @@ -124,6 +124,35 @@ static int EC_FLAGS_MSI; /* Out-of-spec MSI controller */
> >  static int EC_FLAGS_VALIDATE_ECDT; /* ASUStec ECDTs need to be validated */
> >  static int EC_FLAGS_SKIP_DSDT_SCAN; /* Not all BIOS survive early DSDT scan */
> >  
> > +/* notifier chain for who are intresting in ec space changing */
> > +static RAW_NOTIFIER_HEAD(ec_space_chain);
> > +
> > +int __ref register_ec_space_notifier(struct notifier_block *nb)
> > +{
> > +        int ret;
> > +
> > +        ret = raw_notifier_chain_register(&ec_space_chain, nb);
> > +
> > +        return ret;
> > +}
> > +EXPORT_SYMBOL(register_ec_space_notifier);
> > +
> > +void __ref unregister_ec_space_notifier(struct notifier_block *nb)
> > +{
> > +
> > +        raw_notifier_chain_unregister(&ec_space_chain, nb);
> > +}
> > +EXPORT_SYMBOL(unregister_ec_space_notifier);
> > +
> > +static int ec_space_notify(void *data)
> > +{
> > +    int ret;
> > +
> > +    ret = __raw_notifier_call_chain(&ec_space_chain, 0, data, -1, NULL);
> > +
> > +     return notifier_to_errno(ret);
> > +}
> > +
> >  /* --------------------------------------------------------------------------
> >                               Transaction Management
> >     -------------------------------------------------------------------------- */
> > @@ -638,6 +667,9 @@ static u32 acpi_ec_gpe_handler(acpi_handle gpe_device,
> >  		wake_up(&ec->wait);
> >  		ec_check_sci(ec, acpi_ec_read_status(ec));
> >  	}
> > +
> > +	ec_space_notify(data);
> > +
> >  	return ACPI_INTERRUPT_HANDLED | ACPI_REENABLE_GPE;
> >  }
> >  
> > diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> > index 17b5b59..4fe2247 100644
> > --- a/include/linux/acpi.h
> > +++ b/include/linux/acpi.h
> > @@ -158,6 +158,8 @@ extern int ec_transaction(u8 command,
> >                            const u8 *wdata, unsigned wdata_len,
> >                            u8 *rdata, unsigned rdata_len);
> >  extern acpi_handle ec_get_handle(void);
> > +extern int register_ec_space_notifier(struct notifier_block *nb);
> > +extern void unregister_ec_space_notifier(struct notifier_block *nb);
> >  
> >  #if defined(CONFIG_ACPI_WMI) || defined(CONFIG_ACPI_WMI_MODULE)
> >  
> > 


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