Build regressions/improvements in v6.3-rc3 (drm/msm/)

[Geert Uytterhoeven]

Hi Randy,

On Tue, Mar 21, 2023 at 4:10 PM Randy Dunlap <rdunlap at infradead.org> wrote:
> On 3/21/23 00:34, Geert Uytterhoeven wrote:
> > On Tue, Mar 21, 2023 at 6:38 AM Randy Dunlap <rdunlap at 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).
>
> Yes, I installed that same compiler. When I tried to use it, I got:
>
> /opt/crosstool/gcc-5.5.0-nolibc/aarch64-linux/bin/aarch64-linux-gcc: unknown C compiler
> scripts/Kconfig.include:44: Sorry, this C compiler is not supported.

I didn't run into that. I used

make ARCH=arm64
CROSS_COMPILE=/opt/cross/gcc-5.5.0-nolibc/aarch64-linux/bin/aarch64-linux-
drivers/gpu/drm/msm/msm_mdss.o

I did have to disable CONFIG_GCC_PLUGINS, else it couldn't find
<gmp.h>.

> >> @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
>
> OK, I replied to that one.

Thanks!

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at 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