From: David Gibson <david@gibson.dropbear.id.au>
To: linuxppc-embedded@lists.linuxppc.org
Subject: Re: Workaround for USB DMA bugs
Date: Thu, 4 Apr 2002 13:48:09 +1000 [thread overview]
Message-ID: <20020404034809.GL21034@zax> (raw)
In-Reply-To: <3CABC065.6050107@embeddededge.com>
On Wed, Apr 03, 2002 at 09:54:29PM -0500, Dan Malek wrote:
>
> David Gibson wrote:
>
>
> >It's becoming easier though, with the __cacheline_aligned macro. Plus
> >I think if the buffer is individually kmalloc()ed it will be properly
> >aligned.
>
> Alignment is only half the problem. You have to ensure the object is
> modulo cache line size as well. You can't be sharing cache lines subject
> to DMA with other DMA or processor core data.
Oh, right, yes. That was actually what I was meaning when I said
"aligned" (sort of aligned at both ends), forgetting that the normal
meaning only applies to the start address.
--
David Gibson | For every complex problem there is a
david@gibson.dropbear.id.au | solution which is simple, neat and
| wrong. -- H.L. Mencken
http://www.ozlabs.org/people/dgibson
** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
next prev parent reply other threads:[~2002-04-04 3:48 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-04-03 2:43 Workaround for USB DMA bugs David Gibson
2002-04-03 8:17 ` Armin
2002-04-03 17:39 ` Frank Rowand
2002-04-03 17:49 ` Dan Malek
2002-04-03 20:43 ` David Blythe
2002-04-03 23:34 ` David Gibson
2002-04-03 9:45 ` "David Müller (ELSOFT AG)"
2002-04-03 23:35 ` David Gibson
2002-04-03 17:42 ` Dan Malek
2002-04-03 23:40 ` David Gibson
2002-04-04 2:54 ` Dan Malek
2002-04-04 3:48 ` David Gibson [this message]
2002-04-04 4:09 ` Dan Malek
2002-04-04 5:23 ` David Gibson
2002-04-04 6:08 ` Dan Malek
2002-04-04 6:30 ` David Gibson
2002-04-04 20:21 ` David Blythe
2002-04-04 12:35 ` Brad Parker
2002-04-04 14:12 ` Dan Malek
-- strict thread matches above, loose matches on Subject: below --
2002-04-04 4:19 Jeremy Rosen
2002-04-04 6:16 ` Dan Malek
2002-04-04 6:32 ` David Gibson
2002-04-04 6:40 Rosen Jeremy
2002-04-04 6:52 ` David Gibson
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