lkml.org 
[lkml]   [2009]   [Jun]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: PowerPC PCI DMA issues (prefetch/coherency?)

> 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


\
 
 \ /
  Last update: 2009-06-17 10:01    [W:0.098 / U:0.296 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site