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Message-ID: <1524740470.5117.3.camel@suse.de>
Subject: Re: [PATCH] firmware: dmi: Add access to the SKU ID string
From:   Jean Delvare <jdelvare@suse.de>
To:     Vinod Koul <vinod.koul@intel.com>, Simon Glass <sjg@chromium.org>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        C Shapiro <shapiroc@chromium.org>,
        Aaron Durbin <adurbin@chromium.org>,
        Mika Westerberg <mika.westerberg@linux.intel.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Philippe Ombredanne <pombredanne@nexb.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Alex Hung <alex.hung@canonical.com>,
        Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        sayli karnik <karniksayli1995@gmail.com>,
        Sagar Dharia <sdharia@codeaurora.org>
Date:   Thu, 26 Apr 2018 13:01:10 +0200
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         <20180425025125.GH6014@localhost>
         <CAPnjgZ1ExEQHL8W2+k=+wS98O3CCX25dKngv_PFNvgAKVBD4Hw@mail.gmail.com>
         <20180426093324.GV6014@localhost>
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On jeu., 2018-04-26 at 15:03 +0530, Vinod Koul wrote:
> On Wed, Apr 25, 2018 at 03:17:37PM -0600, Simon Glass wrote:
> > 
> > Hi Vinod,
> > 
> > On 24 April 2018 at 20:51, Vinod Koul <vinod.koul@intel.com> wrote:
> > > 
> > > On Tue, Apr 24, 2018 at 03:11:11PM -0600, Simon Glass wrote:
> > > > 
> > > > This is used in some systems from user space for determining the identity
> > > > of the device.
> > > > 
> > > > Expose this as a file so that that user-space tools don't need to read
> > > > from /sys/firmware/dmi/tables/DMI
> > > 
> > > sysfs is an ABI and needs to be documented, I don't see that in this patch,
> > > pls add.
> > 
> > Thanks for taking a look. The only mention of the dmi/id I can find is
> > in Kconfig:
> 
> Sorry I should have been explicit. All sysfs entries are ABI to userspace.
> So they are documented in kernel and the meaning of files should not
> typically get modfied over time.
> Please read Documentation/ABI/README
> 
> For DMI, quick grep told me you should add to
> Documentation/ABI/testing/sysfs-firmware-dmi-tables

No. This is a different interface to user-space (binary tables, instead
of already decoded, selected attributes.)

There is currently no formal documentation of the
/sys/devices/virtual/dmi/id contents, so there's no file Simon can
modify to mention product_sku. Instead, documentation of the whole
directory should be added in a separate patch.

-- 
Jean Delvare
SUSE L3 Support