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Message-ID: <16f727b8-c3b0-c828-0c5b-6728a6e7934f@opensource.wdc.com>
Date:   Tue, 28 Jun 2022 17:59:22 +0900
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Subject: Re: [PATCH] ata: pata_cs5535: Fix W=1 warnings
Content-Language: en-US
To:     John Garry <john.garry@huawei.com>, s.shtylyov@omp.ru
Cc:     linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org
References: <1656335540-50293-1-git-send-email-john.garry@huawei.com>
From:   Damien Le Moal <damien.lemoal@opensource.wdc.com>
Organization: Western Digital Research
In-Reply-To: <1656335540-50293-1-git-send-email-john.garry@huawei.com>
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On 6/27/22 22:12, John Garry wrote:
> x86_64 allmodconfig build with W=3D1 gives these warnings:
>=20
> drivers/ata/pata_cs5535.c: In function =E2=80=98cs5535_set_piomode=E2=80=
=99:
> drivers/ata/pata_cs5535.c:93:11: error: variable =E2=80=98dummy=E2=80=99=
 set but not used [-Werror=3Dunused-but-set-variable]
>   u32 reg, dummy;
>            ^~~~~
> drivers/ata/pata_cs5535.c: In function =E2=80=98cs5535_set_dmamode=E2=80=
=99:
> drivers/ata/pata_cs5535.c:132:11: error: variable =E2=80=98dummy=E2=80=99=
 set but not used [-Werror=3Dunused-but-set-variable]
>   u32 reg, dummy;
>            ^~~~~
> cc1: all warnings being treated as errors
>=20
> Mark variables 'dummy' as "maybe unused" to satisfy when rdmsr() is
> stubbed, which is the same as what we already do in pata_cs5536.c .
>=20
> Signed-off-by: John Garry <john.garry@huawei.com>

Looks good, but I wonder why I am not getting this warning. I always do
W=3D1 and C=3D1 builds. I tried allmodconfig now and I am not getting the
warning...

>=20
> diff --git a/drivers/ata/pata_cs5535.c b/drivers/ata/pata_cs5535.c
> index 6725931f3c35..c2c3238ff84b 100644
> --- a/drivers/ata/pata_cs5535.c
> +++ b/drivers/ata/pata_cs5535.c
> @@ -90,7 +90,7 @@ static void cs5535_set_piomode(struct ata_port *ap, s=
truct ata_device *adev)
>  	static const u16 pio_cmd_timings[5] =3D {
>  		0xF7F4, 0x53F3, 0x13F1, 0x5131, 0x1131
>  	};
> -	u32 reg, dummy;
> +	u32 reg, __maybe_unused dummy;
>  	struct ata_device *pair =3D ata_dev_pair(adev);
> =20
>  	int mode =3D adev->pio_mode - XFER_PIO_0;
> @@ -129,7 +129,7 @@ static void cs5535_set_dmamode(struct ata_port *ap,=
 struct ata_device *adev)
>  	static const u32 mwdma_timings[3] =3D {
>  		0x7F0FFFF3, 0x7F035352, 0x7F024241
>  	};
> -	u32 reg, dummy;
> +	u32 reg, __maybe_unused dummy;
>  	int mode =3D adev->dma_mode;
> =20
>  	rdmsr(ATAC_CH0D0_DMA + 2 * adev->devno, reg, dummy);


--=20
Damien Le Moal
Western Digital Research