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Subject: Re: [PATCH 5/7] dma-mapping: Provide CONFIG_ARCH_DMA_DEFAULT_COHERENT
From:   Jiaxun Yang <jiaxun.yang@flygoat.com>
In-Reply-To: <20230221175842.GD15247@lst.de>
Date:   Tue, 21 Feb 2023 18:18:58 +0000
Cc:     "linux-mips@vger.kernel.org" <linux-mips@vger.kernel.org>,
        linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
        Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
        mpe@ellerman.id.au, paul.walmsley@sifive.com, palmer@dabbelt.com,
        Rob Herring <robh+dt@kernel.org>, m.szyprowski@samsung.com,
        robin.murphy@arm.com
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Message-Id: <9AD04590-81B1-4420-979E-ACC1C7C6C8E8@flygoat.com>
References: <20230221124613.2859-1-jiaxun.yang@flygoat.com>
 <20230221124613.2859-6-jiaxun.yang@flygoat.com>
 <20230221175842.GD15247@lst.de>
To:     Christoph Hellwig <hch@lst.de>
Precedence: bulk


> 2023=E5=B9=B42=E6=9C=8821=E6=97=A5 17:58=EF=BC=8CChristoph Hellwig =
<hch@lst.de> =E5=86=99=E9=81=93=EF=BC=9A
>=20
> On Tue, Feb 21, 2023 at 12:46:11PM +0000, Jiaxun Yang wrote:
>> Provide a kconfig option to allow arches to manipulate default
>> value of dma_default_coherent in Kconfig.
>=20
> I don't see the win over just doing this by setting =
dma_default_coherent
> in the early boot code.

I just don=E2=80=99t want to dig into every archs=E2=80=99 early boot =
code to decide a good
timing for setting this variable.

Also as we do have a OF_DMA_DEFAULT_COHERENT before it makes more
sense to me.

Thanks
- Jiaxun=