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

[Sai Prakash Ranjan <quic_saipraka@quicinc.com>]

On 4/27/2022 9:29 PM, Arnd Bergmann wrote:
> On Thu, Feb 24, 2022 at 7:07 AM Sai Prakash Ranjan
> <quic_saipraka@quicinc.com> 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@arndb.de>
>> Cc: Neil Armstrong <narmstrong@baylibre.com>
>> Reported-by: kernel test robot <lkp@intel.com>
>> Signed-off-by: Sai Prakash Ranjan <quic_saipraka@quicinc.com>
> Reviewed-by: Arnd Bergmann <arnd@arndb.de>
>
> 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