From owner-freebsd-hackers Mon Aug 21 09:20:39 1995 Return-Path: hackers-owner Received: (from majordom@localhost) by freefall.FreeBSD.org (8.6.11/8.6.6) id JAA28126 for hackers-outgoing; Mon, 21 Aug 1995 09:20:39 -0700 Received: from ref.tfs.com (ref.tfs.com [140.145.254.251]) by freefall.FreeBSD.org (8.6.11/8.6.6) with ESMTP id JAA28120 for ; Mon, 21 Aug 1995 09:20:37 -0700 Received: (from julian@localhost) by ref.tfs.com (8.6.11/8.6.9) id JAA23776; Mon, 21 Aug 1995 09:18:21 -0700 From: Julian Elischer Message-Id: <199508211618.JAA23776@ref.tfs.com> Subject: Re: How to abort a DMA transfer ? To: luigi@labinfo.iet.unipi.it (Luigi Rizzo) Date: Mon, 21 Aug 1995 09:18:20 -0700 (PDT) Cc: freebsd-hackers@freebsd.org In-Reply-To: <199508210841.KAA13733@labinfo.iet.unipi.it> from "Luigi Rizzo" at Aug 21, 95 10:41:27 am X-Mailer: ELM [version 2.4 PL24] Content-Type: text Content-Length: 1026 Sender: hackers-owner@freebsd.org Precedence: bulk > 2) the device is closed while the DMA is active (which is essentially > all the times) *and* there will be no further data coming from the > scanner (this is likely: the user knows he wants to close the > device, thus he stops scanning and then gives the appropriate > commands); don't allow the close to complete until the DMA has completed.. > 3) a new open is requested, possibly with different parameters, which > causes the need for a larger buffer; now I need to abort the previous transfer, free the old memory, and malloc a newer block. > > > now)? I would personally do everything in avoiding even touching such > > a hot iron like the DMAC. > +----------------------------------+ ______ _ __ | __--_|\ Julian Elischer | \ U \/ / On assignment | / \ julian@ref.tfs.com +------>x USA \ in a very strange | ( OZ ) 300 lakeside Dr. oakland CA. \___ ___ | country ! +- X_.---._/ USA+(510) 645-3137(wk) \_/ \\ v