Date: Thu, 15 Sep 2005 13:41:41 -0400 From: John Baldwin <jhb@FreeBSD.org> To: src-committers@FreeBSD.org Cc: cvs-src@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/alpha/alpha busdma_machdep.c Message-ID: <200509151341.42862.jhb@FreeBSD.org> In-Reply-To: <200509151709.j8FH9hkm099887@repoman.freebsd.org> References: <200509151709.j8FH9hkm099887@repoman.freebsd.org>
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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. -- 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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