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From:   Geert Uytterhoeven <geert@linux-m68k.org>
Date:   Tue, 21 Mar 2023 08:34:05 +0100
Message-ID: <CAMuHMdWw0OdLPUORh6=Be8AW6bN+Pa2t=dcF47B1m=-ihsNPZQ@mail.gmail.com>
Subject: Re: Build regressions/improvements in v6.3-rc3 (drm/msm/)
To:     Randy Dunlap <rdunlap@infradead.org>
Cc:     linux-kernel@vger.kernel.org, Rob Clark <robdclark@gmail.com>,
        Abhinav Kumar <quic_abhinavk@quicinc.com>,
        Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        linux-arm-msm@vger.kernel.org,
        "dri-devel@lists.freedesktop.org" <dri-devel@lists.freedesktop.org>
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Hi Randy,

On Tue, Mar 21, 2023 at 6:38 AM Randy Dunlap <rdunlap@infradead.org> wrote:
> On 3/20/23 01:21, Geert Uytterhoeven wrote:
> > Below is the list of build error/warning regressions/improvements in
> > v6.3-rc3[1] compared to v6.2[2].
> >
> > Summarized:
> >   - build errors: +9/-14
> >   - build warnings: +4/-1447
> >
> > JFYI, when comparing v6.3-rc3[1] to v6.3-rc2[3], the summaries are:
> >   - build errors: +0/-1
> >   - build warnings: +0/-0
> >
> > Happy fixing! ;-)
> >
> > Thanks to the linux-next team for providing the build service.
> >
> > [1] http://kisskb.ellerman.id.au/kisskb/branch/linus/head/e8d018dd0257f744ca50a729e3d042cf2ec9da65/ (all 152 configs)
> > [2] http://kisskb.ellerman.id.au/kisskb/branch/linus/head/c9c3395d5e3dcc6daee66c6908354d47bf98cb0c/ (all 152 configs)
> > [3] http://kisskb.ellerman.id.au/kisskb/branch/linus/head/eeac8ede17557680855031c6f305ece2378af326/ (all 152 configs)
> >
> >
> > *** ERRORS ***
> >
> > 9 error regressions:
>
> >   + /kisskb/src/drivers/gpu/drm/msm/msm_mdss.c: error: case label does not reduce to an integer constant:  => 300:2, 299:2, 296:2
>
>
> Are these due to the sign bit being set after a shift?
> It looks that way since it is only reported for such values.

Yep.

> From the reports on the build server, it only happens when building with gcc5.
> I don't have the ability to build with gcc5 or I would test it.

I deliberately installed gcc-5.5.0-nolibc/aarch64-linux to reproduce it
(gcc5 on x86 didn't reproduce).

> @Rob and other drm/msm people, what do you think about this?
> (or is this already fixed somewhere but not yet in linux-next?)

Thanks, I posted a similar fix two weeks ago:
https://lore.kernel.org/all/20230306090633.65918-1-geert+renesas@glider.be

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