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From:   Geert Uytterhoeven <geert@linux-m68k.org>
Date:   Wed, 23 Nov 2022 16:49:05 +0100
Message-ID: <CAMuHMdVRZhBECgABtTxe00gM7_EqBaX5auZhmjUfmcLx4zoetQ@mail.gmail.com>
Subject: Re: [PATCH resend] media: staging: stkwebcam: Restore
 MEDIA_{USB,CAMERA}_SUPPORT dependencies
To:     Dan Carpenter <error27@gmail.com>
Cc:     Tommaso Merciai <tommaso.merciai@amarulasolutions.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Hans Verkuil <hverkuil-cisco@xs4all.nl>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Andrzej Pietrasiewicz <andrzejtp2010@gmail.com>,
        Ricardo Ribalda <ribalda@chromium.org>,
        linux-media@vger.kernel.org, linux-staging@lists.linux.dev,
        linux-kernel@vger.kernel.org
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Hi Dan,

On Wed, Nov 23, 2022 at 4:11 PM Dan Carpenter <error27@gmail.com> wrote:
> On Wed, Nov 23, 2022 at 11:13:31AM +0100, Geert Uytterhoeven wrote:
> > On Wed, Nov 23, 2022 at 11:08 AM Tommaso Merciai
> > <tommaso.merciai@amarulasolutions.com> wrote:
> > > On Mon, Nov 21, 2022 at 04:58:33PM +0100, Geert Uytterhoeven wrote:
> > > > By moving support for the USB Syntek DC1125 Camera to staging, the
> > > > dependencies on MEDIA_USB_SUPPORT and MEDIA_CAMERA_SUPPORT were lost.
> > > >
> > > > Fixes: 56280c64ecacc971 ("media: stkwebcam: deprecate driver, move to staging")
> > >
> > > Patch itself looks good but we have some style issue. Applying this
> > > patch I got the following warning from checkpatchl:
> > >
> > > WARNING: Please use correct Fixes: style 'Fixes: <12 chars of sha1> ("<title line>")' - ie: 'Fixes: 56280c64ecac ("media: stkwebcam: deprecate driver, move to staging")'
> > > #10:
> > >
> > > You have to pass only the first 12 chars of the sha1 commit into Fixes
> > > msg:
> > >
> > > Use:
> > >
> > >  Fixes: 56280c64ecac ("media: stkwebcam: deprecate driver, move to staging")
> > >
> > > Instead of:
> > >
> > >  Fixes: 56280c64ecacc971 ("media: stkwebcam: deprecate driver, move to staging")
> >
> > I always use 16 chars, to avoid these becoming ambiguous in a few years.
>
> If we assume hashes are randomly distributed and that people commit
> 100k patches every year then with 12 character we would have 17
> collisions every 1000 years.

So I can expect to see a collision before my retirement day
(which coincides with the signed 32-bit time_t flag day ;-)

BTW, does the above take into account that commit hashes can
collide with other object type hashes, too?

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds