From: Mark Brown <broonie@kernel.org>
To: Michal Suchanek <hramrach@gmail.com>
Cc: "Maxime Ripard" <maxime.ripard@free-electrons.com>,
"Priit Laes" <plaes@plaes.org>, "Chen-Yu Tsai" <wens@csie.org>,
linux-spi <linux-spi@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
"Emilio López" <emilio@elopez.com.ar>
Subject: Re: [PATCH 1/2] spi: sun4i: add DMA support
Date: Thu, 17 Mar 2016 11:43:08 +0000 [thread overview]
Message-ID: <20160317114308.GF2566@sirena.org.uk> (raw)
In-Reply-To: <CAOMqctQzMhR_bf=rMyROcTAPcrgx2EBqhH+qJL=b-U=iG9ZF4Q@mail.gmail.com>
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On Thu, Mar 17, 2016 at 11:58:05AM +0100, Michal Suchanek wrote:
> On 17 March 2016 at 08:27, Maxime Ripard
> > You're mixing two things up: the fact that we can't do more than the
> > FIFO length in PIO and that we're missing DMA support. We have patches
> > to address both, and there's no depedency between the two.
> The only thing is that although DMA is optional on pretty much any
> system you will have DMA available unless you broke your config. You
> really do want the DMA support when it is available. So there will be
> nobody testing the non-DMA part and it will be prone to bitrot.
Well, it might be worth doing PIO for very short transfers even if you
have DMA - it's quite common for this to perform better.
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next prev parent reply other threads:[~2016-03-17 11:43 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-26 5:56 [PATCH RESEND 0/2] spi: sun4i: add DMA support Priit Laes
2016-02-26 5:56 ` [PATCH 1/2] " Priit Laes
2016-02-26 12:25 ` Mark Brown
2016-02-26 12:51 ` Michal Suchanek
2016-03-06 21:42 ` Maxime Ripard
2016-03-10 9:01 ` Michal Suchanek
2016-03-17 7:27 ` Maxime Ripard
2016-03-17 10:58 ` Michal Suchanek
2016-03-17 11:43 ` Mark Brown [this message]
2016-03-17 11:54 ` Michal Suchanek
2016-03-17 11:58 ` Mark Brown
2016-03-18 20:23 ` Maxime Ripard
2016-03-18 20:33 ` Mark Brown
2016-02-26 5:56 ` [PATCH 2/2] ARM: sunxi: spi: add notice about SPI FIFO limit Priit Laes
2016-03-06 18:12 ` Maxime Ripard
2016-02-26 12:15 ` [PATCH RESEND 0/2] spi: sun4i: add DMA support Mark Brown
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