Message-ID: <1481880850.27953.12.camel@sipsolutions.net>
Subject: Re: [PATCH 3/5] firmware: revamp firmware documentation
From: Johannes Berg <johannes@sipsolutions.net>
To: "Luis R. Rodriguez" <mcgrof@kernel.org>,
        =?UTF-8?Q?Rafa=C5=82_Mi=C5=82ecki?= <zajec5@gmail.com>
Cc: Daniel Wagner <daniel.wagner@bmw-carit.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Ming Lei <ming.lei@canonical.com>, Tom Gundersen <teg@jklm.no>,
        Mauro Carvalho Chehab <mchehab@osg.samsung.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Vikram Mulukutla <markivx@codeaurora.org>,
        Stephen Boyd <stephen.boyd@linaro.org>,
        Mark Brown <broonie@kernel.org>, zohar@linux.vnet.ibm.com,
        Takashi Iwai <tiwai@suse.de>,
        Christian Lamparter <chunkeey@googlemail.com>,
        Hauke Mehrtens <hauke@hauke-m.de>,
        Josh Boyer <jwboyer@fedoraproject.org>,
        Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        David Woodhouse <dwmw2@infradead.org>, jslaby@suse.com,
        Linus Torvalds <torvalds@linux-foundation.org>, luto@amacapital.net,
        Fengguang Wu <fengguang.wu@intel.com>,
        Richard Purdie <rpurdie@rpsys.net>,
        Jacek Anaszewski <j.anaszewski@samsung.com>, Abhay_Salunke@dell.com,
        Julia Lawall <Julia.Lawall@lip6.fr>, Gilles.Muller@lip6.fr,
        nicolas.palix@imag.fr, dhowells@redhat.com, bjorn.andersson@linaro.org,
        Arend Van Spriel <arend.vanspriel@broadcom.com>,
        Kalle Valo <kvalo@codeaurora.org>
Date: Fri, 16 Dec 2016 10:34:10 +0100
In-Reply-To: <20161216091851.GN13946@wotan.suse.de>
References: <20161213030828.17820-1-mcgrof@kernel.org>
         <20161213030828.17820-4-mcgrof@kernel.org>
         <ab2f9c97-77a4-e451-c2e5-87076b66a8b6@bmw-carit.de>
         <CACna6rz_TwKkatteuN2f+_mG6gOaDRMuyKTiOb=e=PbRavrS6g@mail.gmail.com>
         <20161216091851.GN13946@wotan.suse.de>
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> > > Maybe it is worth to mention, that the calibration data is unique
> > > to a given chip, so it is individual. That is you would need to
> > > built for each device you sell its own kernel.
> > 
> > It's commonly unique to the device model, not a chip. The same chip
> > can be used with different power amplifiers or different antennas.
> > That's why you need model (board) specific calibration data.
> 
> From what I recall in my 802.11 days this can be often very specific
> per *batch* of cards not just chip/device model, so this depends on
> the manufacturing process and date.

Yes, it can be a per-device calibration done in the factory, and then
the data is programmed into the device after that calibration - but if
the device is something like a router (not a standalone NIC) then the
data might still go through request_firmware() or similar in the end.

johannes