Date: Thu, 13 Nov 2008 15:02:04 -0500 From: John Baldwin <jhb@freebsd.org> To: freebsd-hackers@freebsd.org Cc: Marc =?iso-8859-1?q?L=F6rner?= <marc.loerner@hob.de> Subject: Re: ide with DMA and ram > 4GB Message-ID: <200811131502.04370.jhb@freebsd.org> In-Reply-To: <200811121823.14400.marc.loerner@hob.de> References: <200811121823.14400.marc.loerner@hob.de>
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On Wednesday 12 November 2008 12:23:14 pm Marc L=F6rner wrote: > Hello, > I just stepped over a problem with my IDE disk running in DMA-mode > and having more than 4GB of RAM. > It seems that the whole way down GEOM, ata-disk, ata-dma never is checked > whether physical address of buffer is less than 4GB an so fits in 32bits. > =3D> when PRD is set the address is rigorously truncated to fit into 32bi= t, > with buffer < 4GB all is quite fine. bus_dmamap_load() in ata-dma.c should result in bounce pages being allocate= d=20 and having the data copied to pages below 4GB and having those addresses=20 passed to the callback and stored in the PRD. =2D-=20 John Baldwin
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