Date: Wed, 24 Sep 2003 23:42:55 +0200 From: Vincent Jardin <vjardin@free.fr> To: hackers@freebsd.org Subject: BUS DMA sync Message-ID: <200309242342.55788.vjardin@free.fr>
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Hi, I try to understand the purpose of the PRE sync (BUS_DMASYNC_PREREAD, BUS_DMASYNC_PREWRITE). I understand POST synchronization (BUS_DMASYNC_POSTREAD, BUS_DMASYNC_POSTWRITE) when a device to memory or a memory to device transfert needs to be synchronized. However, what does a synchronization before a transfert mean ? Regards, Vincent
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