Received-SPF: pass (google.com: domain of linux-wireless-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <95fc3b8f-7556-371d-2817-7e0d811de24a@linux.intel.com>
Date:   Tue, 19 Jul 2022 09:49:44 -0500
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101
 Firefox/91.0 Thunderbird/91.11.0
Subject: Re: [PATCH] docs: driver-api: firmware: add driver firmware
 guidelines.
Content-Language: en-US
To:     Dave Airlie <airlied@gmail.com>,
        Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc:     alsa-devel@alsa-project.org,
        "open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jonathan Corbet <corbet@lwn.net>,
        Linux Wireless List <linux-wireless@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>, linux-block@vger.kernel.org,
        "Luis R. Rodriguez" <mcgrof@kernel.org>,
        Daniel Vetter <daniel@ffwll.ch>,
        Network Development <netdev@vger.kernel.org>,
        "dri-devel@lists.sf.net" <dri-devel@lists.sf.net>,
        Dave Airlie <airlied@redhat.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Linux Media Mailing List <linux-media@vger.kernel.org>
References: <20220718072144.2699487-1-airlied@gmail.com>
 <YtWeUOJewho7p/vM@intel.com>
 <CAPM=9tyhOfOz1tn7uNsg_0EzvrBHcSoY+8bignNb2zfgZr6iRw@mail.gmail.com>
From:   Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
In-Reply-To: <CAPM=9tyhOfOz1tn7uNsg_0EzvrBHcSoY+8bignNb2zfgZr6iRw@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Precedence: bulk


On 7/18/22 19:29, Dave Airlie wrote:
>>> +* Firmware should be versioned with at least a major/minor version. It
>>> +  is suggested that the firmware files in linux-firmware be named with
>>> +  some device specific name, and just the major version. The
>>> +  major/minor/patch versions should be stored in a header in the
>>> +  firmware file for the driver to detect any non-ABI fixes/issues. The
>>> +  firmware files in linux-firmware should be overwritten with the newest
>>> +  compatible major version. Newer major version firmware should remain
>>> +  compatible with all kernels that load that major number.
>>
>> would symbolic links be acceptable in the linux-firmware.git where
>> the <fmw>_<major>.bin is a sym link to <fwm>_<major>.<minor>.bin
>>
>> or having the <fwm>_<major>.bin really to be the overwritten every minor
>> update?
> 
> I don't think providing multiple minor versions of fw in
> linux-firmware is that interesting.
> Like if the major is the same, surely you always want the newer ones.
> As long as the
> ABI doesn't break. Otherwise we are just wasting disk space with fws
> nobody will be using.

It was my understanding that once a firmware file is in linux-firmware
it's there forever. There are tons of existing symlinks to point to the
latest version, but the previous versions are not removed/overwritten.

see random examples:
ls -lR /lib/firmware  | grep t4fw
ls -lR /lib/firmware  | grep fw_release