From owner-freebsd-hackers Sun Aug 20 10:01:13 1995 Return-Path: hackers-owner Received: (from majordom@localhost) by freefall.FreeBSD.org (8.6.11/8.6.6) id KAA08119 for hackers-outgoing; Sun, 20 Aug 1995 10:01:13 -0700 Received: from labinfo.iet.unipi.it (labinfo.iet.unipi.it [131.114.9.5]) by freefall.FreeBSD.org (8.6.11/8.6.6) with ESMTP id KAA08112 for ; Sun, 20 Aug 1995 10:01:02 -0700 Received: from localhost (luigi@localhost) by labinfo.iet.unipi.it (8.6.5/8.6.5) id TAA12803 for freebsd-hackers@freebsd.org; Sun, 20 Aug 1995 19:01:01 +0200 From: Luigi Rizzo Message-Id: <199508201701.TAA12803@labinfo.iet.unipi.it> Subject: How to abort a DMA transfer ? To: freebsd-hackers@freebsd.org Date: Sun, 20 Aug 1995 19:01:00 +0200 (MET DST) X-Mailer: ELM [version 2.4 PL23] Content-Type: text Content-Length: 822 Sender: hackers-owner@freebsd.org Precedence: bulk How (within a device driver) do I abort a DMA transfer which has been started but has not completed yet ? I am having this problem in the driver for a hand-scanner (the scanner does some read ahead; meanwhile, a user might close the device and we want to abort the transfer and free the buffer). I am surprised I haven't seen (or understood!) anything like this in existing drivers, not even in the floppy driver! Thanks Luigi ==================================================================== Luigi Rizzo Dip. di Ingegneria dell'Informazione email: luigi@iet.unipi.it Universita' di Pisa tel: +39-50-568533 via Diotisalvi 2, 56126 PISA (Italy) fax: +39-50-568522 http://www.iet.unipi.it/~luigi/ ====================================================================