Re: [PATCH v7] Add new mac80211 driver mwlwifi.

[Kalle Valo <kvalo@codeaurora.org>]

Grant Grundler <grundler@google.com> writes:

> Sorry for the late response...just one point below
>
> On Fri, Nov 20, 2015 at 3:22 AM, Johannes Berg <johannes@sipsolutions.net>
> wrote:
>
>     > +#define MWL_DRV_NAME     KBUILD_MODNAME
>     > +#define MWL_DRV_VERSION       "10.3.0.14"
>
>     versions like that are generally fairly useless since you don't update
>     them for every commit ...
>
>
> When backporting to other kernel trees, it's extremely handy to have a
> DRV_VERSION.
>
> Checking if a particular kernel build has the expected driver version trivial.
>  "mod_info" dumps the driver version for modules (which this will usually be
> too).
>
> And yes, it won't get updated for every commit only because other version
> control might encapsulate those changes. Not every distro makes their build
> versioning accessible to outsiders. So it's still helpful even if not perfect.
>
> Marvell can update this every time they resync with their own internal
> versions.

But the problem is that you cannot really trust this driver version
string. I found a perfect example from another Marvell driver:

5e6e3a92b9a4c drivers/net/wireless/mwifiex/main.c (Bing Zhao 2011-03-21 18:00:50 -0700   25) #define VERSION   "1.0"

So nobody has updated that version string since the initial commit from
2011 and that driver has had over 900 non-merge commits after that.
Because of bad cases like this I think having a driver specific versions
in in-tree drivers are just noise and unnecessary extra work. When
porting a driver to another tree git commit ids, release tag names or
git-describe output are much better ways to identify the driver version.

-- 
Kalle Valo