From: linux@arm.linux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: Problem with non aligned DMA in usbnet on ARM
Date: Wed, 11 Aug 2010 21:35:05 +0100 [thread overview]
Message-ID: <20100811203505.GA463@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <4C62C7B3.2030706@nvidia.com>
On Wed, Aug 11, 2010 at 08:54:27AM -0700, Gary King wrote:
> On 08/11/2010 04:38 AM, Martin Fuzzey wrote:
> > It seems to me these fixup functions are not intended to solve
> > alignment issues but rather implement device specific framing (such as
> > when the hardware packs multiple ethernet frames into a single urb)
> >
> I sent a patch to the list about 2 weeks ago that added support to
> DMA bounce to bounce for misaligned buffers. We have a similar
> problem with URB alignment for usbnet on Tegra's HCD:
>
> http://lists.arm.linux.org.uk/lurker/message/20100729.005746.b43fa1d9.en.html
We don't want to add support for this to DMA bounce. DMA bounce is already
a pain in the backside and causes its own set of problems - please let it
die a long slow but quite death.
If you want to see the kind of pain dmabounce causes, look at this long
standing and as yet unsolved bug:
http://bugzilla.kernel.org/show_bug.cgi?id=7760
next prev parent reply other threads:[~2010-08-11 20:35 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-11 9:41 Problem with non aligned DMA in usbnet on ARM Martin Fuzzey
2010-08-11 9:54 ` Russell King - ARM Linux
2010-08-11 10:11 ` Martin Fuzzey
2010-08-11 15:04 ` Greg KH
2010-08-11 16:08 ` Martin Fuzzey
2010-08-11 17:42 ` Greg KH
2010-08-11 19:07 ` Martin Fuzzey
2010-08-11 20:13 ` Greg KH
2010-08-11 22:31 ` Martin Fuzzey
2010-08-12 17:01 ` Matthieu CASTET
2010-08-11 19:10 ` Oliver Neukum
2010-08-11 9:59 ` Matthieu CASTET
2010-08-11 11:38 ` Martin Fuzzey
2010-08-11 15:54 ` Gary King
2010-08-11 20:35 ` Russell King - ARM Linux [this message]
2010-08-11 22:20 ` Martin Fuzzey
2010-08-11 22:47 ` Russell King - ARM Linux
2010-08-12 17:08 ` Matthieu CASTET
2010-08-13 10:06 ` Martin Fuzzey
2010-08-13 10:58 ` Oliver Neukum
2010-08-13 13:42 ` David Brownell
2010-08-13 13:53 ` Oliver Neukum
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