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From: Matthias Brugger <matthias.bgg@gmail.com>
To: Miles Chen <miles.chen@mediatek.com>,
	Chun-Kuang Hu <chunkuang.hu@kernel.org>,
	Philipp Zabel <p.zabel@pengutronix.de>,
	David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Jie Qiu <jie.qiu@mediatek.com>,
	Junzhi Zhao <junzhi.zhao@mediatek.com>
Cc: Zhiqiang Lin <zhiqiang.lin@mediatek.com>,
	CK Hu <ck.hu@mediatek.com>,
	dri-devel@lists.freedesktop.org,
	linux-mediatek@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, llvm@lists.linux.dev
Subject: Re: [PATCH v3] drm/mediatek: Fix unused-but-set variable warning
Date: Thu, 30 Dec 2021 13:29:54 +0100	[thread overview]
Message-ID: <d784e170-a115-bd0a-a87c-07aed0fb73fc@gmail.com> (raw)
In-Reply-To: <20211230093610.28012-1-miles.chen@mediatek.com>



On 30/12/2021 10:36, Miles Chen wrote:
> clang reports a unused-but-set variable warning:
> drivers/gpu/drm/mediatek/mtk_cec.c:85:6: warning: variable 'tmp' set but not used [-Wunused-but-set-variable]
> 
> In current implementation, mtk_cec_mask() writes val into target register
> and ignores the mask. After talking to our hdmi experts, mtk_cec_mask()
> should read a register, clean only mask bits, and update (val | mask) bits
> to the register.
> 
> Fixes: 8f83f26891e1 ("drm/mediatek: Add HDMI support")
> 
> Cc: Zhiqiang Lin <zhiqiang.lin@mediatek.com>
> Cc: CK Hu <ck.hu@mediatek.com>
> Cc: Matthias Brugger <matthias.bgg@gmail.com>
> 
> Signed-off-by: Miles Chen <miles.chen@mediatek.com>

I'm still not happy with the commit subject, I think it is misleading. Clang 
only helped to find the bug, but the we are fixing something else, that's not 
just a clang warning. But I don't want to nit-pick too much so:

Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>

> 
> ---
> 
> Change since v1:
> add Fixes tag
> 
> Change since v2:
> add explanation of mtk_cec_mask()
> 
> Change-Id: Iec6402b0532942f4d0e8bc56817eb87b95c03fad
> ---
>   drivers/gpu/drm/mediatek/mtk_cec.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_cec.c b/drivers/gpu/drm/mediatek/mtk_cec.c
> index e9cef5c0c8f7..cdfa648910b2 100644
> --- a/drivers/gpu/drm/mediatek/mtk_cec.c
> +++ b/drivers/gpu/drm/mediatek/mtk_cec.c
> @@ -85,7 +85,7 @@ static void mtk_cec_mask(struct mtk_cec *cec, unsigned int offset,
>   	u32 tmp = readl(cec->regs + offset) & ~mask;
>   
>   	tmp |= val & mask;
> -	writel(val, cec->regs + offset);
> +	writel(tmp, cec->regs + offset);
>   }
>   
>   void mtk_cec_set_hpd_event(struct device *dev,
> 

_______________________________________________
Linux-mediatek mailing list
Linux-mediatek@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-mediatek

WARNING: multiple messages have this Message-ID (diff)
From: Matthias Brugger <matthias.bgg@gmail.com>
To: Miles Chen <miles.chen@mediatek.com>,
	Chun-Kuang Hu <chunkuang.hu@kernel.org>,
	Philipp Zabel <p.zabel@pengutronix.de>,
	David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Jie Qiu <jie.qiu@mediatek.com>,
	Junzhi Zhao <junzhi.zhao@mediatek.com>
Cc: Zhiqiang Lin <zhiqiang.lin@mediatek.com>,
	CK Hu <ck.hu@mediatek.com>,
	dri-devel@lists.freedesktop.org,
	linux-mediatek@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, llvm@lists.linux.dev
Subject: Re: [PATCH v3] drm/mediatek: Fix unused-but-set variable warning
Date: Thu, 30 Dec 2021 13:29:54 +0100	[thread overview]
Message-ID: <d784e170-a115-bd0a-a87c-07aed0fb73fc@gmail.com> (raw)
In-Reply-To: <20211230093610.28012-1-miles.chen@mediatek.com>



On 30/12/2021 10:36, Miles Chen wrote:
> clang reports a unused-but-set variable warning:
> drivers/gpu/drm/mediatek/mtk_cec.c:85:6: warning: variable 'tmp' set but not used [-Wunused-but-set-variable]
> 
> In current implementation, mtk_cec_mask() writes val into target register
> and ignores the mask. After talking to our hdmi experts, mtk_cec_mask()
> should read a register, clean only mask bits, and update (val | mask) bits
> to the register.
> 
> Fixes: 8f83f26891e1 ("drm/mediatek: Add HDMI support")
> 
> Cc: Zhiqiang Lin <zhiqiang.lin@mediatek.com>
> Cc: CK Hu <ck.hu@mediatek.com>
> Cc: Matthias Brugger <matthias.bgg@gmail.com>
> 
> Signed-off-by: Miles Chen <miles.chen@mediatek.com>

I'm still not happy with the commit subject, I think it is misleading. Clang 
only helped to find the bug, but the we are fixing something else, that's not 
just a clang warning. But I don't want to nit-pick too much so:

Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>

> 
> ---
> 
> Change since v1:
> add Fixes tag
> 
> Change since v2:
> add explanation of mtk_cec_mask()
> 
> Change-Id: Iec6402b0532942f4d0e8bc56817eb87b95c03fad
> ---
>   drivers/gpu/drm/mediatek/mtk_cec.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_cec.c b/drivers/gpu/drm/mediatek/mtk_cec.c
> index e9cef5c0c8f7..cdfa648910b2 100644
> --- a/drivers/gpu/drm/mediatek/mtk_cec.c
> +++ b/drivers/gpu/drm/mediatek/mtk_cec.c
> @@ -85,7 +85,7 @@ static void mtk_cec_mask(struct mtk_cec *cec, unsigned int offset,
>   	u32 tmp = readl(cec->regs + offset) & ~mask;
>   
>   	tmp |= val & mask;
> -	writel(val, cec->regs + offset);
> +	writel(tmp, cec->regs + offset);
>   }
>   
>   void mtk_cec_set_hpd_event(struct device *dev,
> 

WARNING: multiple messages have this Message-ID (diff)
From: Matthias Brugger <matthias.bgg@gmail.com>
To: Miles Chen <miles.chen@mediatek.com>,
	Chun-Kuang Hu <chunkuang.hu@kernel.org>,
	Philipp Zabel <p.zabel@pengutronix.de>,
	David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Jie Qiu <jie.qiu@mediatek.com>,
	Junzhi Zhao <junzhi.zhao@mediatek.com>
Cc: Zhiqiang Lin <zhiqiang.lin@mediatek.com>,
	CK Hu <ck.hu@mediatek.com>,
	dri-devel@lists.freedesktop.org,
	linux-mediatek@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, llvm@lists.linux.dev
Subject: Re: [PATCH v3] drm/mediatek: Fix unused-but-set variable warning
Date: Thu, 30 Dec 2021 13:29:54 +0100	[thread overview]
Message-ID: <d784e170-a115-bd0a-a87c-07aed0fb73fc@gmail.com> (raw)
In-Reply-To: <20211230093610.28012-1-miles.chen@mediatek.com>



On 30/12/2021 10:36, Miles Chen wrote:
> clang reports a unused-but-set variable warning:
> drivers/gpu/drm/mediatek/mtk_cec.c:85:6: warning: variable 'tmp' set but not used [-Wunused-but-set-variable]
> 
> In current implementation, mtk_cec_mask() writes val into target register
> and ignores the mask. After talking to our hdmi experts, mtk_cec_mask()
> should read a register, clean only mask bits, and update (val | mask) bits
> to the register.
> 
> Fixes: 8f83f26891e1 ("drm/mediatek: Add HDMI support")
> 
> Cc: Zhiqiang Lin <zhiqiang.lin@mediatek.com>
> Cc: CK Hu <ck.hu@mediatek.com>
> Cc: Matthias Brugger <matthias.bgg@gmail.com>
> 
> Signed-off-by: Miles Chen <miles.chen@mediatek.com>

I'm still not happy with the commit subject, I think it is misleading. Clang 
only helped to find the bug, but the we are fixing something else, that's not 
just a clang warning. But I don't want to nit-pick too much so:

Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>

> 
> ---
> 
> Change since v1:
> add Fixes tag
> 
> Change since v2:
> add explanation of mtk_cec_mask()
> 
> Change-Id: Iec6402b0532942f4d0e8bc56817eb87b95c03fad
> ---
>   drivers/gpu/drm/mediatek/mtk_cec.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_cec.c b/drivers/gpu/drm/mediatek/mtk_cec.c
> index e9cef5c0c8f7..cdfa648910b2 100644
> --- a/drivers/gpu/drm/mediatek/mtk_cec.c
> +++ b/drivers/gpu/drm/mediatek/mtk_cec.c
> @@ -85,7 +85,7 @@ static void mtk_cec_mask(struct mtk_cec *cec, unsigned int offset,
>   	u32 tmp = readl(cec->regs + offset) & ~mask;
>   
>   	tmp |= val & mask;
> -	writel(val, cec->regs + offset);
> +	writel(tmp, cec->regs + offset);
>   }
>   
>   void mtk_cec_set_hpd_event(struct device *dev,
> 

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

WARNING: multiple messages have this Message-ID (diff)
From: Matthias Brugger <matthias.bgg@gmail.com>
To: Miles Chen <miles.chen@mediatek.com>,
	Chun-Kuang Hu <chunkuang.hu@kernel.org>,
	Philipp Zabel <p.zabel@pengutronix.de>,
	David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Jie Qiu <jie.qiu@mediatek.com>,
	Junzhi Zhao <junzhi.zhao@mediatek.com>
Cc: llvm@lists.linux.dev, linux-kernel@vger.kernel.org,
	dri-devel@lists.freedesktop.org,
	Zhiqiang Lin <zhiqiang.lin@mediatek.com>,
	linux-mediatek@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v3] drm/mediatek: Fix unused-but-set variable warning
Date: Thu, 30 Dec 2021 13:29:54 +0100	[thread overview]
Message-ID: <d784e170-a115-bd0a-a87c-07aed0fb73fc@gmail.com> (raw)
In-Reply-To: <20211230093610.28012-1-miles.chen@mediatek.com>



On 30/12/2021 10:36, Miles Chen wrote:
> clang reports a unused-but-set variable warning:
> drivers/gpu/drm/mediatek/mtk_cec.c:85:6: warning: variable 'tmp' set but not used [-Wunused-but-set-variable]
> 
> In current implementation, mtk_cec_mask() writes val into target register
> and ignores the mask. After talking to our hdmi experts, mtk_cec_mask()
> should read a register, clean only mask bits, and update (val | mask) bits
> to the register.
> 
> Fixes: 8f83f26891e1 ("drm/mediatek: Add HDMI support")
> 
> Cc: Zhiqiang Lin <zhiqiang.lin@mediatek.com>
> Cc: CK Hu <ck.hu@mediatek.com>
> Cc: Matthias Brugger <matthias.bgg@gmail.com>
> 
> Signed-off-by: Miles Chen <miles.chen@mediatek.com>

I'm still not happy with the commit subject, I think it is misleading. Clang 
only helped to find the bug, but the we are fixing something else, that's not 
just a clang warning. But I don't want to nit-pick too much so:

Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>

> 
> ---
> 
> Change since v1:
> add Fixes tag
> 
> Change since v2:
> add explanation of mtk_cec_mask()
> 
> Change-Id: Iec6402b0532942f4d0e8bc56817eb87b95c03fad
> ---
>   drivers/gpu/drm/mediatek/mtk_cec.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_cec.c b/drivers/gpu/drm/mediatek/mtk_cec.c
> index e9cef5c0c8f7..cdfa648910b2 100644
> --- a/drivers/gpu/drm/mediatek/mtk_cec.c
> +++ b/drivers/gpu/drm/mediatek/mtk_cec.c
> @@ -85,7 +85,7 @@ static void mtk_cec_mask(struct mtk_cec *cec, unsigned int offset,
>   	u32 tmp = readl(cec->regs + offset) & ~mask;
>   
>   	tmp |= val & mask;
> -	writel(val, cec->regs + offset);
> +	writel(tmp, cec->regs + offset);
>   }
>   
>   void mtk_cec_set_hpd_event(struct device *dev,
> 

  reply	other threads:[~2021-12-30 12:30 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-30  9:36 [PATCH v3] drm/mediatek: Fix unused-but-set variable warning Miles Chen
2021-12-30  9:36 ` Miles Chen
2021-12-30  9:36 ` Miles Chen
2021-12-30  9:36 ` Miles Chen
2021-12-30 12:29 ` Matthias Brugger [this message]
2021-12-30 12:29   ` Matthias Brugger
2021-12-30 12:29   ` Matthias Brugger
2021-12-30 12:29   ` Matthias Brugger
  -- strict thread matches above, loose matches on Subject: below --
2021-12-28 14:53 [PATCH] " Matthias Brugger
2022-01-02 23:46 ` [PATCH v3] " miles.chen
2022-01-02 23:46   ` miles.chen
2022-01-02 23:46   ` miles.chen
2022-01-02 23:46   ` miles.chen
2022-01-07  1:40   ` Miles Chen
2022-01-07  1:40     ` Miles Chen
2022-01-07  1:40     ` Miles Chen
2022-01-07  1:40     ` Miles Chen

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