Date: Wed, 8 Jul 2009 11:03:43 +0200 From: Hans Petter Selasky <hselasky@c2i.net> To: Rafal Jaworowski <raj@semihalf.com> Cc: thompsa@freebsd.org, freebsd-arm@freebsd.org, freebsd-usb@freebsd.org Subject: Re: CPU Cache and busdma usage in USB Message-ID: <200907081103.45388.hselasky@c2i.net> In-Reply-To: <37C51279-42D8-49DE-8249-0DA386EBB062@semihalf.com> References: <200906231035.43096.kosmo@semihalf.com> <200907071846.42086.hselasky@c2i.net> <37C51279-42D8-49DE-8249-0DA386EBB062@semihalf.com>
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On Wednesday 08 July 2009 10:58:17 Rafal Jaworowski wrote: > On 2009-07-07, at 18:46, Hans Petter Selasky wrote: > >> I had Checked USB behaviour on PowerPC without hardware cache > >> coherency. > >> The problem also exists here and patch helps. > > > > In my source code view the busdma sync function is empty for power- > > pc. Your > > patch should have no effect at all for sync operations? > > This was about the PPC4xx PowerPC port, not committed to the tree yet. > Unlike most PowerPC this system has a de-coherent DMA and therefore > its busdma sync is non empty, but needs to enforce coherency by > software. > > The point is this is another platform on which USB stack (usb_pc_cpu_* > functions) shows similar issues as reported for ARM and MIPS. And what about my patch suggestion in my previous e-mail having the same subject. Does it work? Regarding my testing on the AT91RM9200 I was short of time yesterday and will try to get it done today. --HPS
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