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Date: Thu, 29 Jun 2017 10:01:05 -0700
From: Stephen Hemminger <stephen@networkplumber.org>
To: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Mauro Carvalho Chehab <mchehab@s-opensource.com>,
        devel@driverdev.osuosl.org, linux-fbdev@vger.kernel.org,
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        Linux Kernel Mailinglist <linux-kernel@vger.kernel.org>,
        Hans Verkuil <hans.verkuil@cisco.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        linux-media@vger.kernel.org
Subject: Re: [PATCH RESEND 0/7] Introduce MEDIA_VERSION to end
 KENREL_VERSION abuse in media
Message-ID: <20170629100105.6af3b77a@xeon-e3>
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On Thu, 29 Jun 2017 11:42:59 +0200
Johannes Thumshirn <jthumshirn@suse.de> wrote:

> On Sat, Jun 24, 2017 at 05:15:07PM -0300, Mauro Carvalho Chehab wrote:
> > Sorry, but I can't see any advantage on it. On the downside, it
> > includes the media controller header file (media.h) where it
> > is not needed.  
> 
> My reasoning was the differences in semantics. KERNEL_VERSION() is for
> encoding the kernel's version triplet not a API or Hardware or whatever
> version. Other subsystems do this as well, for instance in NVMe we have the
> NVME_VS() macro which is used to encode the NVMe Spec compliance from a human
> readable form to the hardware's u32. Also KERNEL_VERISON() shouldn't have
> in-tree users IMHO. Yes there is _one_ other user of it in-tree which is EXT4
> and I already talked to Jan Kara about it and we decided to leave it in until
> 4.20.
> 
> Byte,
> 	Johannes

If you read Linus's comments on version.
Driver version is meaningless and there is a desire to rip it out of all
drivers. The reason is that drivers must always behave the same, i.e you
can't use version to change API/ABI behavior. 

Any upstream driver should never use KERNEL_VERSION().