From: Chris Pringle <chris.pringle@oxtel.com>
To: Scott Wood <scottwood@freescale.com>
Cc: linux-kernel@vger.kernel.org,
"linuxppc-dev@ozlabs.org list" <linuxppc-dev@lists.ozlabs.org>
Subject: Re: PowerPC PCI DMA issues (prefetch/coherency?)
Date: Wed, 17 Jun 2009 08:58:19 +0100 [thread overview]
Message-ID: <4A38A21B.5060306@oxtel.com> (raw)
In-Reply-To: <4A37D073.6020802@freescale.com>
> You could enable CONFIG_NOT_COHERENT_CACHE.
>
I've just tried this (I had to edit Kconfig in power/platforms to make
the build system accept it), and interestingly it's making no
difference. I'm using streaming mappings, and are using the pci_map_sg
functions to ensure the memory is mapped/flushed correctly. I've also
explicitly put in a pci_dma_sync_sg_for_device, however that's also not
made any difference. Turning the cpu cache snoop off has the same affect
as it did without CONFIG_NOT_COHERENT_CACHE; it gets much worse. Any
other ideas?
Will back off the low latency patches next, and give 2.6.30 a try - see
if that makes any difference.
--
______________________________
Chris Pringle
Software Engineer
Miranda Technologies Ltd.
Hithercroft Road
Wallingford
Oxfordshire OX10 9DG
UK
Tel. +44 1491 820206
Fax. +44 1491 820001
www.miranda.com
____________________________
Miranda Technologies Limited
Registered in England and Wales CN 02017053
Registered Office: James House, Mere Park, Dedmere Road, Marlow, Bucks, SL7 1FJ
WARNING: multiple messages have this Message-ID (diff)
From: Chris Pringle <chris.pringle@oxtel.com>
To: Scott Wood <scottwood@freescale.com>
Cc: "linuxppc-dev@ozlabs.org list" <linuxppc-dev@lists.ozlabs.org>,
linux-kernel@vger.kernel.org
Subject: Re: PowerPC PCI DMA issues (prefetch/coherency?)
Date: Wed, 17 Jun 2009 08:58:19 +0100 [thread overview]
Message-ID: <4A38A21B.5060306@oxtel.com> (raw)
In-Reply-To: <4A37D073.6020802@freescale.com>
> You could enable CONFIG_NOT_COHERENT_CACHE.
>
I've just tried this (I had to edit Kconfig in power/platforms to make
the build system accept it), and interestingly it's making no
difference. I'm using streaming mappings, and are using the pci_map_sg
functions to ensure the memory is mapped/flushed correctly. I've also
explicitly put in a pci_dma_sync_sg_for_device, however that's also not
made any difference. Turning the cpu cache snoop off has the same affect
as it did without CONFIG_NOT_COHERENT_CACHE; it gets much worse. Any
other ideas?
Will back off the low latency patches next, and give 2.6.30 a try - see
if that makes any difference.
--
______________________________
Chris Pringle
Software Engineer
Miranda Technologies Ltd.
Hithercroft Road
Wallingford
Oxfordshire OX10 9DG
UK
Tel. +44 1491 820206
Fax. +44 1491 820001
www.miranda.com
____________________________
Miranda Technologies Limited
Registered in England and Wales CN 02017053
Registered Office: James House, Mere Park, Dedmere Road, Marlow, Bucks, SL7 1FJ
next prev parent reply other threads:[~2009-06-17 7:58 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-16 13:58 PowerPC PCI DMA issues (prefetch/coherency?) Chris Pringle
2009-06-16 14:16 ` Michael S. Zick
2009-06-16 14:59 ` Hu Gang
2009-06-16 16:21 ` Scott Wood
2009-06-16 16:34 ` Chris Pringle
2009-06-16 16:46 ` Scott Wood
2009-06-16 16:46 ` Scott Wood
2009-06-16 16:57 ` Chris Pringle
2009-06-16 16:57 ` Chris Pringle
2009-06-16 17:03 ` Scott Wood
2009-06-16 17:03 ` Scott Wood
2009-06-16 17:43 ` Arnd Bergmann
2009-06-16 17:49 ` Scott Wood
2009-06-16 17:49 ` Scott Wood
2009-06-16 18:02 ` Arnd Bergmann
2009-06-16 18:02 ` Arnd Bergmann
2009-06-17 0:18 ` Benjamin Herrenschmidt
2009-06-17 0:37 ` FUJITA Tomonori
2009-06-17 0:37 ` FUJITA Tomonori
2009-06-17 0:56 ` Leon Woestenberg
2009-06-17 0:56 ` Leon Woestenberg
2009-06-17 1:08 ` Benjamin Herrenschmidt
2009-06-17 1:08 ` Benjamin Herrenschmidt
2009-06-17 1:13 ` Leon Woestenberg
2009-06-17 1:13 ` Leon Woestenberg
2009-06-17 1:07 ` Benjamin Herrenschmidt
2009-06-17 1:07 ` Benjamin Herrenschmidt
2009-06-17 7:58 ` Chris Pringle [this message]
2009-06-17 7:58 ` Chris Pringle
2009-06-17 13:18 ` Chris Pringle
2009-06-18 11:24 ` Chris Pringle
2009-06-22 14:31 ` AW: " Sergej.Stepanov
2009-06-22 14:31 ` Sergej.Stepanov
2009-06-29 8:11 ` Chris Pringle
2009-06-16 14:08 Chris Pringle
2009-06-16 15:48 ` Roderick Colenbrander
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