Re: [PATCHv10 4/6] drm/meson: Fix overflow implicit truncation warnings

[Sai Prakash Ranjan]

On 4/27/2022 9:29 PM, Arnd Bergmann wrote:
> On Thu, Feb 24, 2022 at 7:07 AM Sai Prakash Ranjan
> <quic_saipraka@xxxxxxxxxxx> wrote:
> > Fix -Woverflow warnings for drm/meson driver which is a result
> > of moving arm64 custom MMIO accessor macros to asm-generic function
> > implementations giving a bonus type-checking now and uncovering these
> > overflow warnings.
> >
> > drivers/gpu/drm/meson/meson_viu.c: In function ‘meson_viu_init’:
> > drivers/gpu/drm/meson/meson_registers.h:1826:48: error: large integer implicitly truncated to unsigned type [-Werror=overflow]
> >   #define  VIU_OSD_BLEND_REORDER(dest, src)      ((src) << (dest * 4))
> >                                                  ^
> > drivers/gpu/drm/meson/meson_viu.c:472:18: note: in expansion of macro ‘VIU_OSD_BLEND_REORDER’
> >     writel_relaxed(VIU_OSD_BLEND_REORDER(0, 1) |
> >                    ^~~~~~~~~~~~~~~~~~~~~
> >
> > Cc: Arnd Bergmann <arnd@xxxxxxxx>
> > Cc: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
> > Reported-by: kernel test robot <lkp@xxxxxxxxx>
> > Signed-off-by: Sai Prakash Ranjan <quic_saipraka@xxxxxxxxxxx>
> Reviewed-by: Arnd Bergmann <arnd@xxxxxxxx>
>
> It took me a bit to understand why we got the warning in the first place, but I
> should have just read the patch description, it's all there....

Right :)

Thanks,
Sai