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 16:52:58 +1000 [thread overview]
Message-ID: <20020404065258.GV21034@zax> (raw)
In-Reply-To: <200204041445.g34Ejjc14079@gt_tus_au.au.thalesgroup.com>
On Thu, Apr 04, 2002 at 04:40:00PM +1000, Rosen Jeremy wrote:
>
> >
> > This flag is used on architectures that have memory only accessible
> > from the processor, not from a DMA device, to ensure a DMA device
> > gets a memory bank that it can access.
>
> so it specifies that the kmalloc()ed region must be usable for DMA
> transfer.... which is exactly what we want.
Not really - IIRC it really is specific to ISA DMA. PCI devices on
i386 won't generally need it and probably won't specify it. Nor would
we want to, since that would put everything in the ludicrously small
ISA DMA region (only 1MB AFAIR) which could rapidly be exhausted.
--
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 6:52 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-04-04 6:40 Workaround for USB DMA bugs Rosen Jeremy
2002-04-04 6:52 ` David Gibson [this message]
-- 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
2002-04-03 2:43 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
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
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