From: Wolfram Sang <wsa@the-dreams.de>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Vinod Koul <vinod.koul@intel.com>,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
Magnus Damm <magnus.damm@gmail.com>,
Linux I2C <linux-i2c@vger.kernel.org>,
Linux-sh list <linux-sh@vger.kernel.org>,
Simon Horman <horms@verge.net.au>,
dmaengine@vger.kernel.org
Subject: Re: [PATCH 2/5] i2c: sh_mobile: add DMA support
Date: Mon, 15 Dec 2014 10:06:28 +0100 [thread overview]
Message-ID: <20141215090628.GB1031@katana> (raw)
In-Reply-To: <CAMuHMdWsUkQN-+h07Zf2snbD9bEw49_+rasY4zS8QcvqA+aXUQ@mail.gmail.com>
[-- Attachment #1: Type: text/plain, Size: 778 bytes --]
> Please let me summarize...
Thanks for the summary, Geert!
> Solutions under consideration:
> 1. Wolfram posted a patch to make i2c-sh_mobile fall back to PIO,
> and retry DMA initialization in every request, so it will switch to
> DMA when it becomes available. But this is suboptimal, as it adds
> overhead to every request (and DMA may never become available in
> case 2).
Still, I'd think I should repost my patches with your comments
addressed. It does add a bit of overhead IF the dmaengine core is
compiled in AND the driver for the DMA hardware is not. Well, yeah. On
the other hand, it fixes the regression that the driver is not even
loaded in that case (because it currently will be deferred endlessly).
What do you think?
All the best,
Wolfram
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next prev parent reply other threads:[~2014-12-15 9:06 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-07 10:11 [PATCH 0/5] i2c: sh_mobile: add DMA support Wolfram Sang
2014-11-07 10:11 ` [PATCH 1/5] i2c: sh_mobile: sort includes alphabetically Wolfram Sang
2014-11-12 16:10 ` Wolfram Sang
2014-11-07 10:11 ` [PATCH 2/5] i2c: sh_mobile: add DMA support Wolfram Sang
2014-11-12 16:11 ` Wolfram Sang
2014-12-09 10:53 ` Geert Uytterhoeven
2014-12-09 14:09 ` Wolfram Sang
2014-12-10 5:44 ` Magnus Damm
2014-12-10 8:01 ` Wolfram Sang
2014-12-10 14:19 ` Laurent Pinchart
2014-12-10 14:23 ` Wolfram Sang
2014-12-11 5:02 ` Vinod Koul
2014-12-11 7:37 ` Wolfram Sang
2014-12-11 7:47 ` Laurent Pinchart
2014-12-11 8:28 ` Wolfram Sang
2014-12-11 21:42 ` Laurent Pinchart
2014-12-11 21:47 ` Wolfram Sang
2014-12-11 21:52 ` Laurent Pinchart
2014-12-12 11:07 ` Wolfram Sang
2014-12-15 6:43 ` Vinod Koul
2014-12-15 8:31 ` Geert Uytterhoeven
2014-12-15 9:06 ` Wolfram Sang [this message]
2014-12-15 9:32 ` Geert Uytterhoeven
2014-12-15 9:13 ` Vinod Koul
[not found] ` <20141215091314.GQ16827-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
2014-12-15 9:42 ` Laurent Pinchart
2014-12-15 14:48 ` Vinod Koul
2014-12-15 9:45 ` Wolfram Sang
2014-12-15 14:50 ` Vinod Koul
2014-11-07 10:11 ` [PATCH 3/5] i2c: sh_mobile: improve success message Wolfram Sang
2014-11-12 16:12 ` Wolfram Sang
2014-11-13 0:27 ` Simon Horman
2014-11-07 10:11 ` [PATCH 4/5] ARM: shmobile: r8a7790: add DMA nodes for IIC Wolfram Sang
2014-11-13 0:26 ` Simon Horman
2014-11-07 10:11 ` [PATCH 5/5] ARM: shmobile: r8a7791: " Wolfram Sang
2014-11-13 0:26 ` Simon Horman
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