Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Mon, 1 Nov 2021 22:57:57 +0800
From:   Chen Yu <yu.c.chen@intel.com>
To:     Andy Shevchenko <andriy.shevchenko@intel.com>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-acpi@vger.kernel.org,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Ard Biesheuvel <ardb@kernel.org>, Len Brown <lenb@kernel.org>,
        Ashok Raj <ashok.raj@intel.com>,
        Mike Rapoport <rppt@kernel.org>,
        Aubrey Li <aubrey.li@intel.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v7 2/4] drivers/acpi: Introduce Platform Firmware Runtime
 Update device driver
Message-ID: <20211101145757.GA35522@chenyu5-mobl1>
References: <cover.1635317102.git.yu.c.chen@intel.com>
 <a318e4edc13e5a3ff95b901871b8929746535715.1635317102.git.yu.c.chen@intel.com>
 <YXkn8aBvAVEXxgdp@smile.fi.intel.com>
 <20211101093320.GA18982@chenyu5-mobl1>
 <YX/NwEdw26wzKFvQ@smile.fi.intel.com>
 <20211101131434.GA32880@chenyu5-mobl1>
 <YX/ouT/hi5ccaxsz@kroah.com>
 <YX/0yCUlGM35vEXS@smile.fi.intel.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <YX/0yCUlGM35vEXS@smile.fi.intel.com>
Precedence: bulk

On Mon, Nov 01, 2021 at 04:08:08PM +0200, Andy Shevchenko wrote:
> On Mon, Nov 01, 2021 at 02:16:41PM +0100, Greg Kroah-Hartman wrote:
> > On Mon, Nov 01, 2021 at 09:14:34PM +0800, Chen Yu wrote:
> > > On Mon, Nov 01, 2021 at 01:21:36PM +0200, Andy Shevchenko wrote:
> 
> ...
> 
> > > Ok, I'll switch to global variables in next version.
> > 
> > Wait, no, why?
> 
> But why should we have a duplication of basically static data?
> 
> > Keep them per-device unless you can somehow be
> > guaranteed there will never be more than one of these ACPI devices in a
> > system.
> 
> I guess you missed my point. These definitions are _always_ the same.
> It does not matter how many devices in the system.
> 
> Chen, is my perception correct?
> If no, then do what Greg says.
>
Yes, there would be only one PFRU ACPI object in the system.
And for PFRU Telemetry ACPI object, I don't know if the specification
would introduce separate telemetry log using different uuid in the
future - Currently there are two telemetry log buffers share the same
uuid). Maybe for scalability reason we can make them per device.
> > It's simpler this way, no need to worry about global state at
> > all.
> 
> Actually I have no idea why we even have strings in  and not raw buffers.
> Moreover, I haven't got why even we have them in uAPI.
I see. These uuid could be put into the .c and there is no need for the
user to be aware of these values.

thanks,
Chenyu
> 
> -- 
> With Best Regards,
> Andy Shevchenko
> 
>