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Message-ID: <65531cb4-efff-1e0e-2bac-7c7759ff55cd@quicinc.com>
Date:   Thu, 28 Apr 2022 08:33:15 +0530
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Subject: Re: [PATCHv10 4/6] drm/meson: Fix overflow implicit truncation
 warnings
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To:     Arnd Bergmann <arnd@arndb.de>
CC:     Will Deacon <will@kernel.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Marc Zyngier <maz@kernel.org>,
        "Trilok Soni" <quic_tsoni@quicinc.com>,
        <quic_psodagud@quicinc.com>, gregkh <gregkh@linuxfoundation.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-arm-msm <linux-arm-msm@vger.kernel.org>,
        Neil Armstrong <narmstrong@baylibre.com>,
        kernel test robot <lkp@intel.com>
References: <cover.1644824638.git.quic_saipraka@quicinc.com>
 <9c7ff199d826b60e019c0eeeb6aa280abfdb9a82.1644824638.git.quic_saipraka@quicinc.com>
 <CAK8P3a3_Ea2Szn61D-t--52V-zk+B-sq2mi5YbfMbTim7M9ZAQ@mail.gmail.com>
From:   Sai Prakash Ranjan <quic_saipraka@quicinc.com>
In-Reply-To: <CAK8P3a3_Ea2Szn61D-t--52V-zk+B-sq2mi5YbfMbTim7M9ZAQ@mail.gmail.com>
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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