Date: Tue, 21 Apr 2009 12:28:31 -0700 From: Marcel Moolenaar <xcllnt@mac.com> To: Rafal Jaworowski <raj@semihalf.com> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, Marcel Moolenaar <marcel@freebsd.org>, src-committers@freebsd.org Subject: Re: svn commit: r191362 - head/sys/powerpc/booke Message-ID: <93F1ADEF-9B5D-4855-AB35-91E9687A3512@mac.com> In-Reply-To: <2610CF8A-83E5-4CDF-9704-CC1BC1897F7C@semihalf.com> References: <200904211704.n3LH41DN016572@svn.freebsd.org> <2610CF8A-83E5-4CDF-9704-CC1BC1897F7C@semihalf.com>
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On Apr 21, 2009, at 11:00 AM, Rafal Jaworowski wrote: > On 2009-04-21, at 19:04, Marcel Moolenaar wrote: > >> o Carve out the first 1MB of physical memory. The MPC85xx has >> DMA problems with addresses below 1MB. Ideally busdma knows >> how to avoid allocating below 1MB for MPC85xx, but that >> requires a bit more work. For now, ignore the 1MB of DRAM. > > Could you elaborate a bit on the last item? What is the faulty > scenario, is this a known h/w defect documented somewhere? Not documented and no indication of a failure from PCI/PCI-X or PCI Express host controllers, nor the device doing the DMA and also not from the coherency engine on the MPC85xx. The only noticeable behaviour is a lack of data transfer by virtue of having unchanged memory after DMA write completion. Observed with MPC8544 PCI, MPC8544 PCI Express and MPC8548 PCI Express. FYI, -- Marcel Moolenaar xcllnt@mac.com
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