Date: Wed, 8 Jul 2009 12:16:39 +0200 From: Piotr =?iso-8859-2?q?Zi=EAcik?= <kosmo@semihalf.com> To: Hans Petter Selasky <hselasky@c2i.net> Cc: Rafal Jaworowski <raj@semihalf.com>, freebsd-arm@freebsd.org, thompsa@freebsd.org, freebsd-usb@freebsd.org Subject: Re: CPU Cache and busdma usage in USB Message-ID: <200907081216.40100.kosmo@semihalf.com> In-Reply-To: <200907081103.45388.hselasky@c2i.net> References: <200906231035.43096.kosmo@semihalf.com> <37C51279-42D8-49DE-8249-0DA386EBB062@semihalf.com> <200907081103.45388.hselasky@c2i.net>
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Wednesday 08 July 2009 11:03:43 Hans Petter Selasky napisał(a): > > And what about my patch suggestion in my previous e-mail having the same > subject. Does it work? > I have tested it and it does not work. By the way Writeback before Writeback Invalidate did not change cache behaviour too much. Writeback invalidate means flush all modified cache lines and then invalidate cache. However looking into logs which I have sent you yesterdat I see one difference which may be significant. My patch changes Invalidate into Writeback Invalidate. In original code if driver write something to memory and then invalidate cache, the write will be lost. With my patch after change will be written to memory and then cache will be invalidated. What do you think ? -- Best Regards, Piotr Ziecik
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