Date: Fri, 11 Jun 2010 11:52:45 -0700 From: Pyun YongHyeon <pyunyh@gmail.com> To: Marcel Moolenaar <xcllnt@mac.com> Cc: svn-src-head@freebsd.org, Scott Long <scottl@samsco.org>, src-committers@freebsd.org, svn-src-all@freebsd.org, John Baldwin <jhb@freebsd.org> Subject: Re: svn commit: r209026 - in head/sys/ia64: ia64 include Message-ID: <20100611185245.GK13776@michelle.cdnetworks.com> In-Reply-To: <C939F25F-6501-4CBA-8087-8E5D1591EBCF@mac.com> References: <19B0DF11-5998-40F5-8095-8D2521B1C597@mac.com> <EE4B5C07-194D-4408-B0A1-BA25BE39468F@samsco.org> <291D17F7-F387-4A13-8ED9-2898A9F7E018@mac.com> <028BA7D4-90C8-4D2D-B9A5-C1C3CF9B6D7D@samsco.org> <20100611174137.GC13776@michelle.cdnetworks.com> <9F065122-7D91-42E9-A251-5AF4AAF0B4E5@samsco.org> <20100611175016.GD13776@michelle.cdnetworks.com> <59E450BB-1E79-440E-AF82-B78E1E8FE334@mac.com> <20100611180824.GG13776@michelle.cdnetworks.com> <C939F25F-6501-4CBA-8087-8E5D1591EBCF@mac.com>
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On Fri, Jun 11, 2010 at 11:49:14AM -0700, Marcel Moolenaar wrote: > > On Jun 11, 2010, at 11:08 AM, Pyun YongHyeon wrote: > > > On Fri, Jun 11, 2010 at 11:06:06AM -0700, Marcel Moolenaar wrote: > >> > >> On Jun 11, 2010, at 10:50 AM, Pyun YongHyeon wrote: > >> > >>>>>> > >>>>>> I'm not clear why you even need bounce buffers for RX. The chip supports 64bit addresses with no boundary or alignment restrictions. > >>>>>> > >>>>> > >>>>> Some controllers have 4G boundary bug so bge(4) restricts dma > >>>>> address space. > >>>> > >>>> That limitation should be reflected in the boundary attribute of the tag, not the lowaddr/highaddr attributes. > >>>> > >>> > >>> Yes, but that needed more code. And I don't have these buggy > >>> controllers so I chose more simple way that would work even though > >>> it may be inefficient. > >> > >> Do you happen to know if one or both of the hardware I have access to > >> is the "buggy" hardware? > >> > > > > Yes, both devices below can not handle 4GB boundary crossing in DMA > > state machine. > > Thanks. I'll keep that in mind. If I have a few cycles I'll patch the > kernel to allow 64-bit DMA addresses with a 4G boundary restriction > and run that through stress2. > I'll let you know when I have a patch to try on your box. I'm not sure when that could be done though. > -- > Marcel Moolenaar > xcllnt@mac.com > > >
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