From: Jonathan Cameron <jic23@kernel.org>
To: Lars-Peter Clausen <lars@metafoo.de>
Cc: Alexandru Ardelean <ardeleanalex@gmail.com>,
Hartmut Knaack <knaack.h@gmx.de>,
Peter Meerwald-Stadler <pmeerw@pmeerw.net>,
Alexandru Ardelean <alexandru.ardelean@analog.com>,
linux-iio <linux-iio@vger.kernel.org>
Subject: Re: [PATCH] iio: buffer-dmaengine: adjust `bytes_used` with residue info
Date: Sun, 30 Aug 2020 12:10:30 +0100 [thread overview]
Message-ID: <20200830121030.66420067@archlinux> (raw)
In-Reply-To: <f336acac-ed70-ad88-57ca-8d06ec54182e@metafoo.de>
On Sat, 29 Aug 2020 20:30:04 +0200
Lars-Peter Clausen <lars@metafoo.de> wrote:
> On 8/29/20 5:51 PM, Jonathan Cameron wrote:
> > On Wed, 26 Aug 2020 09:36:39 +0300
> > Alexandru Ardelean <ardeleanalex@gmail.com> wrote:
> >
> >> On Wed, Aug 26, 2020 at 8:22 AM Lars-Peter Clausen <lars@metafoo.de> wrote:
> >>> From: Alexandru Ardelean <alexandru.ardelean@analog.com>
> >>>
> >>> A transfer may fall shorter than the bytes in the block.
> >>> This information is available in the residue from the DMA engine, so we can
> >>> compute actual `bytes_used` with that by subtracting the residue.
> >>>
> >> This was in my pipeline as well [obviously].
> >> Thanks :)
> >>
> >>> Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
> >>> Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
> > "smells" like a fix. Is it? Or are we looking at something that
> > only matters for some future hardware, or an optmization?
> >
> > If it's a fix, where is the fixes tag?
>
> It's a feature :)
>
> When we first added the IIO DMA buffer support this API did not exist in
> dmaengine. So for the longest time most DMA drivers did not have the
> ability to report short transfers. Primarily because in many cases the
> hardware doesn't even support it.
>
> Now with this patch the IIO DMA buffer implementation supports systems
> where the DMA can generate short transfers.
Applied to the togreg branch of iio.git and pushed out as testing for
the autobuilders to play with it.
Thanks,
Jonathan
>
> - Lars
>
prev parent reply other threads:[~2020-08-30 11:10 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-26 5:20 [PATCH] iio: buffer-dmaengine: adjust `bytes_used` with residue info Lars-Peter Clausen
2020-08-26 6:36 ` Alexandru Ardelean
2020-08-29 15:51 ` Jonathan Cameron
2020-08-29 18:30 ` Lars-Peter Clausen
2020-08-30 11:10 ` Jonathan Cameron [this message]
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