From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Oliver Neukum <oliver@neukum.org>,
"Shilimkar, Santosh" <santosh.shilimkar@ti.com>,
Matthew Dharm <mdharm-kernel@one-eyed-alien.net>,
Ming Lei <tom.leiming@gmail.com>,
"Mankad, Maulik Ojas" <x0082077@ti.com>,
Sergei Shtylyov <sshtylyov@ru.mvista.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Sebastian Siewior <bigeasy@linutronix.de>,
"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Pavel Machek <pavel@ucw.cz>, Greg KH <greg@kroah.com>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
Subject: Re: USB mass storage and ARM cache coherency
Date: Wed, 17 Feb 2010 09:55:53 +0000 [thread overview]
Message-ID: <20100217095553.GA30033@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <1266397543.16346.264.camel@pasglop>
On Wed, Feb 17, 2010 at 08:05:43PM +1100, Benjamin Herrenschmidt wrote:
> On Tue, 2010-02-16 at 09:22 +0100, Oliver Neukum wrote:
> > This seems wrong to me. Buffers for control transfers may be
> > transfered
> > by DMA, so the caches must be flushed on architectures whose caches
> > are not coherent with respect to DMA.
> >
> > Would you care to elaborate on the exact nature of the bug you are
> > fixing?
>
> I missed part of this thread, so forgive me if I'm a bit off here, but
> if the problem is indeed I$/D$ cache coherency vs. PIO transfers, then
> this is a long solved issue on other archs such as ppc (and I _think_
> sparc).
Nope. It's to do with mapping a buffer for DMA, and then doing PIO
reads/writes to it.
With speculative prefetches, you have to deal with cache coherency with
hardware DMA on DMA unmap. If you've written to the buffer in violation
of the DMA API buffer ownership rules, then your writes get thrown away
resulting in immediate data corruption.
next prev parent reply other threads:[~2010-02-17 9:59 UTC|newest]
Thread overview: 193+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-29 14:34 USB mass storage and ARM cache coherency Catalin Marinas
2010-01-29 16:10 ` Oliver Neukum
2010-01-29 16:23 ` Ming Lei
2010-01-29 16:34 ` Catalin Marinas
2010-01-29 16:41 ` Oliver Neukum
2010-01-29 17:14 ` Catalin Marinas
2010-01-29 17:51 ` Sergei Shtylyov
2010-01-29 18:54 ` Matthew Dharm
2010-01-29 19:35 ` Greg KH
2010-02-01 13:49 ` Catalin Marinas
2010-02-01 17:29 ` Catalin Marinas
2010-02-01 20:14 ` Alan Stern
2010-02-02 4:24 ` Paul Mundt
2010-02-02 9:58 ` Catalin Marinas
2010-02-01 22:30 ` Andreas Mohr
2010-02-02 6:58 ` Oliver Neukum
2010-02-02 9:31 ` Florian Fainelli
2010-02-02 6:39 ` Paul Mundt
2010-02-02 11:05 ` Catalin Marinas
2010-02-02 11:15 ` Paul Mundt
2010-02-02 9:11 ` Sebastian Andrzej Siewior
2010-02-02 11:09 ` Catalin Marinas
2010-02-02 11:48 ` Oliver Neukum
2010-02-02 12:01 ` Catalin Marinas
2010-02-02 12:07 ` Oliver Neukum
2010-02-02 12:11 ` Andreas Mohr
2010-02-02 14:42 ` Clemens Ladisch
2010-02-02 14:52 ` Oliver Neukum
2010-02-02 15:10 ` Andreas Mohr
2010-02-02 15:34 ` Catalin Marinas
2010-02-02 20:38 ` Andreas Mohr
2010-02-02 12:39 ` Catalin Marinas
2010-02-02 13:08 ` Oliver Neukum
2010-02-02 14:34 ` Catalin Marinas
2010-02-02 17:11 ` Alan Stern
2010-02-02 17:20 ` Catalin Marinas
2010-02-02 21:52 ` Andreas Mohr
2010-02-03 15:15 ` Alan Stern
2010-02-08 6:55 ` Pavel Machek
2010-02-02 13:36 ` Ming Lei
2010-02-02 14:35 ` Catalin Marinas
2010-02-08 6:55 ` Pavel Machek
2010-02-08 7:33 ` Andreas Mohr
2010-02-08 10:19 ` Catalin Marinas
2010-02-08 9:51 ` Catalin Marinas
2010-02-08 10:03 ` Andy Green
2010-02-17 9:50 ` Sascha Hauer
2010-02-17 9:57 ` Andy Green
2010-02-08 10:52 ` Pavel Machek
2010-02-08 11:28 ` Catalin Marinas
2010-02-16 7:57 ` Shilimkar, Santosh
2010-02-16 8:22 ` Oliver Neukum
2010-02-16 8:55 ` Shilimkar, Santosh
2010-02-16 9:07 ` Oliver Neukum
2010-02-16 9:39 ` Russell King - ARM Linux
2010-02-16 13:32 ` Oliver Neukum
2010-02-16 13:40 ` Shilimkar, Santosh
2010-02-16 13:46 ` Oliver Neukum
2010-02-16 14:12 ` Shilimkar, Santosh
2010-02-16 14:22 ` Oliver Neukum
2010-02-16 14:45 ` Shilimkar, Santosh
2010-02-16 15:44 ` Alan Stern
2010-02-17 8:55 ` Shilimkar, Santosh
2010-02-17 9:10 ` Oliver Neukum
2010-02-17 9:17 ` Shilimkar, Santosh
2010-02-17 17:02 ` Alan Stern
2010-02-17 20:26 ` Russell King - ARM Linux
2010-02-17 20:30 ` Gadiyar, Anand
2010-02-18 6:56 ` Oliver Neukum
2010-02-18 7:14 ` Gadiyar, Anand
2010-02-17 12:29 ` Jamie Lokier
2010-02-17 3:21 ` Ming Lei
2010-02-17 9:05 ` Benjamin Herrenschmidt
2010-02-17 9:15 ` Oliver Neukum
2010-02-17 9:40 ` Benjamin Herrenschmidt
2010-02-17 10:09 ` Oliver Neukum
2010-02-17 10:18 ` Benjamin Herrenschmidt
2010-02-17 10:23 ` Oliver Neukum
2010-02-17 12:15 ` Benjamin Herrenschmidt
2010-02-17 9:55 ` Russell King - ARM Linux [this message]
2010-02-17 10:05 ` Benjamin Herrenschmidt
2010-02-17 15:27 ` Catalin Marinas
2010-02-17 20:37 ` Benjamin Herrenschmidt
2010-02-17 20:44 ` Russell King - ARM Linux
2010-02-17 22:31 ` Benjamin Herrenschmidt
2010-02-19 17:15 ` Catalin Marinas
2010-02-19 17:36 ` Catalin Marinas
2010-02-19 20:53 ` Oliver Neukum
2010-02-24 2:48 ` Benjamin Herrenschmidt
2010-02-24 7:16 ` Oliver Neukum
2010-02-24 21:12 ` Benjamin Herrenschmidt
2010-02-25 3:48 ` Oliver Neukum
2010-02-26 0:22 ` Benjamin Herrenschmidt
2010-02-25 12:36 ` James Bottomley
2010-02-24 2:47 ` Benjamin Herrenschmidt
2010-02-24 16:19 ` Alan Stern
2010-02-24 21:13 ` Benjamin Herrenschmidt
2010-02-24 21:50 ` Alan Stern
2010-02-25 20:52 ` Benjamin Herrenschmidt
2010-02-26 16:00 ` Catalin Marinas
2010-02-26 21:36 ` Benjamin Herrenschmidt
2010-02-26 16:25 ` Catalin Marinas
2010-02-26 16:52 ` Alan Stern
2010-02-26 21:51 ` Benjamin Herrenschmidt
2010-02-26 21:00 ` Russell King - ARM Linux
2010-02-28 0:14 ` Benjamin Herrenschmidt
2010-02-28 5:01 ` James Bottomley
2010-03-01 10:39 ` Catalin Marinas
2010-03-01 11:06 ` Russell King - ARM Linux
2010-03-02 12:11 ` FUJITA Tomonori
2010-03-02 17:05 ` Catalin Marinas
2010-03-02 17:47 ` Catalin Marinas
2010-03-02 23:33 ` Benjamin Herrenschmidt
2010-03-03 10:21 ` Catalin Marinas
2010-03-02 23:29 ` Benjamin Herrenschmidt
2010-03-03 3:47 ` FUJITA Tomonori
2010-03-03 5:10 ` Benjamin Herrenschmidt
2010-03-03 5:40 ` James Bottomley
2010-03-03 9:36 ` Russell King - ARM Linux
2010-03-03 10:24 ` James Bottomley
2010-03-03 19:41 ` Russell King - ARM Linux
2010-03-04 2:00 ` Benjamin Herrenschmidt
2010-03-04 8:26 ` James Bottomley
2010-03-04 21:25 ` Benjamin Herrenschmidt
2010-03-03 6:35 ` FUJITA Tomonori
2010-03-03 10:43 ` Catalin Marinas
2010-03-03 10:40 ` Catalin Marinas
2010-03-03 21:54 ` Pavel Machek
2010-03-04 13:35 ` Catalin Marinas
2010-03-04 13:51 ` Pavel Machek
2010-03-04 14:21 ` James Bottomley
2010-03-04 14:27 ` Russell King - ARM Linux
2010-03-04 15:25 ` Catalin Marinas
2010-03-04 15:34 ` Russell King - ARM Linux
2010-03-04 21:31 ` Benjamin Herrenschmidt
2010-03-06 10:47 ` James Bottomley
2010-03-06 19:36 ` Russell King - ARM Linux
2010-03-06 21:07 ` Benjamin Herrenschmidt
2010-03-07 5:54 ` James Bottomley
2010-03-08 11:17 ` Catalin Marinas
2010-03-06 21:03 ` Benjamin Herrenschmidt
2010-03-07 3:37 ` James Bottomley
2010-03-08 8:46 ` FUJITA Tomonori
2010-03-09 2:25 ` Benjamin Herrenschmidt
2010-03-04 15:29 ` Catalin Marinas
2010-03-04 15:41 ` Paul Mundt
2010-03-04 16:30 ` Russell King - ARM Linux
2010-03-04 17:34 ` Catalin Marinas
2010-03-04 17:54 ` Russell King - ARM Linux
2010-03-04 22:27 ` Andreas Mohr
2010-03-04 18:07 ` Catalin Marinas
2010-03-04 21:37 ` Benjamin Herrenschmidt
2010-03-04 22:11 ` Catalin Marinas
2010-03-05 4:34 ` Benjamin Herrenschmidt
2010-03-05 9:27 ` Catalin Marinas
2010-03-05 1:17 ` Paul Mundt
2010-03-05 4:44 ` Benjamin Herrenschmidt
2010-03-10 3:52 ` Paul Mundt
2010-03-11 21:44 ` Benjamin Herrenschmidt
2010-03-04 21:34 ` Benjamin Herrenschmidt
2010-03-04 21:28 ` Benjamin Herrenschmidt
2010-03-04 21:40 ` Russell King - ARM Linux
2010-03-05 4:31 ` Benjamin Herrenschmidt
2010-03-04 15:35 ` Catalin Marinas
2010-03-07 8:23 ` Pavel Machek
2010-03-08 10:57 ` Catalin Marinas
2010-03-02 23:26 ` Benjamin Herrenschmidt
2010-03-01 10:42 ` Catalin Marinas
2010-03-03 20:24 ` Jamie Lokier
2010-02-26 21:40 ` Benjamin Herrenschmidt
2010-02-26 21:49 ` Russell King - ARM Linux
2010-02-28 0:24 ` Benjamin Herrenschmidt
2010-02-28 19:17 ` Pavel Machek
2010-03-01 11:10 ` Catalin Marinas
2010-03-02 4:11 ` Benjamin Herrenschmidt
2010-02-24 2:39 ` Benjamin Herrenschmidt
2010-02-26 16:44 ` Catalin Marinas
2010-02-26 21:49 ` Benjamin Herrenschmidt
2010-02-26 22:03 ` Russell King - ARM Linux
2010-02-28 0:29 ` Benjamin Herrenschmidt
2010-02-28 23:20 ` Catalin Marinas
2010-02-28 23:17 ` Catalin Marinas
2010-02-17 15:27 ` Catalin Marinas
2010-02-17 15:39 ` Catalin Marinas
2010-02-17 15:40 ` Catalin Marinas
2010-02-17 15:40 ` Catalin Marinas
2010-02-17 16:19 ` Catalin Marinas
2010-02-17 16:19 ` Catalin Marinas
2010-02-16 8:44 ` Russell King - ARM Linux
2010-02-16 8:51 ` Gadiyar, Anand
2010-02-20 7:21 ` Pete Zaitcev
-- strict thread matches above, loose matches on Subject: below --
2010-02-03 23:56 George Spelvin
2010-02-04 4:39 ` Paul Mundt
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