Date: Thu, 15 Sep 2005 15:22:37 -0400 From: John Baldwin <jhb@FreeBSD.org> To: Scott Long <scottl@samsco.org> Cc: cvs-src@FreeBSD.org, src-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/alpha/alpha busdma_machdep.c Message-ID: <200509151522.39043.jhb@FreeBSD.org> In-Reply-To: <4329C835.6020104@samsco.org> References: <200509151709.j8FH9hkm099887@repoman.freebsd.org> <200509151341.42862.jhb@FreeBSD.org> <4329C835.6020104@samsco.org>
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On Thursday 15 September 2005 03:15 pm, Scott Long wrote: > John Baldwin wrote: > > On Thursday 15 September 2005 01:09 pm, John Baldwin wrote: > >>jhb 2005-09-15 17:09:42 UTC > >> > >> FreeBSD src repository > >> > >> Modified files: > >> sys/alpha/alpha busdma_machdep.c > >> Log: > >> Add a memory barrier for PREWRITE operations to ensure all writes by > >> the CPU have drained before further writes to kick off the operation. > > > > Other architectures with relaxed memory ordering probably also need thus > > such as ia64, powerpc, and perhaps amd64. sparc64 already has a barrier. > > BTW, it seems that the bus_dma code could be somewhat simplified if > > there was a sys/kern/subr_busdma.c that contained routines to implement > > bounce buffers that could be used by the MD code since the MD code that > > does do bounce pages tends to duplicate a lot of stuff between the > > different archs. > > Indeed it does, and if you want to work on it, please feel free to send > it to me for > review. I can tack it onto my todo list but it'll be buried. :) I was hoping someone else might be able to hack on it and pass it off to you for review. :) -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" = http://www.FreeBSD.org
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